Bearing for use in sliding head restraint

ABSTRACT

The present disclosure relates to bearings, guide sleeves and head restraint assemblies for automobiles.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority under 35 U.S.C. §119(e) to U.S. PatentApplication No. 61/841,315 entitled “BEARING FOR USE IN SLIDING HEADRESTRAINT,” by Timothy J. Hagan et al., filed Jun. 29, 2013; claimspriority under 35 U.S.C. §119(e) to U.S. Patent Application No.61/841,316 entitled “BEARING FOR USE IN SLIDING HEAD RESTRAINT,” byTimothy J. Hagan et al., filed Jun. 29, 2013; claims priority under 35U.S.C. §119(e) to U.S. Patent Application No. 61/841,317 entitled“BEARING FOR USE IN SLIDING HEAD RESTRAINT,” by Timothy J. Hagan et al.,filed Jun. 29, 2013; claims priority under 35 U.S.C. §119(e) to U.S.Patent Application No. 61/884,767 entitled “BEARING FOR USE IN SLIDINGHEAD RESTRAINT,” by Timothy J. Hagan et al., filed Sep. 30, 2013; andclaims priority under 35 U.S.C. §119(e) to U.S. Patent Application No.61/921,806, entitled “BEARING FOR USE IN SLIDING HEAD RESTRAINT,” byTimothy J. Hagan et al., filed Dec. 30, 2013, of which all are assignedto the current assignee hereof and incorporated herein by reference intheir entirety.

FIELD OF THE DISCLOSURE

The present disclosure relates to bearings, guide sleeves and headrestraint assemblies for automobiles.

RELATED ART

Automotive vehicles include vehicle seat assemblies for supportingvehicle occupants. The seat assemblies typically include a substantiallyhorizontal seat cushion and a generally upright seat back pivotallyconnected to the seat cushion by a rotatable mechanism. Seat assembliesalso typically include a head restraint extending from a top face of theseat back. The head restraint is typically movable between a pluralityof head restraint positions relative to the seat back to accommodate awide range of occupant heights.

It is widely practiced in automotive seat assemblies to support the headrestraint at the top of the seat back with a spaced apart pair of posts.Each of the posts can extend outward from the head restraint and can beinserted into a corresponding mounting fixture in the seat back.

Either one or both of the posts typically contain a plurality ofexternal notches arranged longitudinally thereon, representing thecorresponding plurality of head restraint selectable positions. Aplunger or depressor can be engaged with any one of the plurality ofnotches to maintain the head restraint in the corresponding head supportposition. The plunger is typically spring biased such that in the biasedposition, the plunger engages with one of the notches, thus preventingaxial translation of the head restraint relative the seat back.

To adjust the height of the head restraint, a vehicle occupant candepress the plunger, causing the plunger to disengage from a notch onthe post. After the plunger disengages from the notch, the occupant canapply a force to the head restraint, causing the entire head restraintassembly to translate in the desired vertical direction. For example, tolower the height of the head restraint, the occupant can urge theassembly towards the seat back. Conversely, to increase the height ofthe head restraint, the occupant can urge the assembly away from theseat back.

After the occupant has positioned the head restraint at the desiredheight, the occupant can release the plunger, allowing the plunger toonce again bias against the post. If at this time the plunger is alignedwith one of the notches, the plunger can engage therewith, causing thehead restraint to securely lock in that position. However, if theplunger is not aligned with a notch, the occupant must then urge thehead restraint in either vertical direction until the plunger engageswith the nearest notch, at which point the head restraint is securelylocked.

Previous adjustable head restraint assemblies have relied on intentionalmisalignment of the posts relative to the engagement fixture in the seatback. This misalignment can allow the posts to form an interference fitwith the mounting fixture of the seat back. This misalignment hasseveral undesirable consequences. Particularly, the misalignment cancause the assembly to exhibit a high seat assembly to seat assemblyvariability, such as in terms of ease of headrest adjustment and/ortolerances. Moreover, the misalignment can cause undesirable noise,vibration, and harshness characteristics.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are illustrated by way of example and are not limited in theaccompanying figures.

FIG. 1 includes an exploded perspective view of a head restraintassembly in accordance with an embodiment.

FIG. 2 includes a perspective view of a head restraint assembly inaccordance with an embodiment.

FIG. 3A includes a cross-sectional side plan view of a head restraintassembly in accordance with an embodiment.

FIG. 3B includes a perspective view of a guide sleeve in accordance withan embodiment.

FIG. 4 includes a cross-sectional side view of a stop feature adapted toengage a post within a guide sleeve in accordance with an embodiment.

FIG. 5 includes a perspective view of a bearing in accordance with anembodiment.

FIG. 6 includes a side plan view of a bearing in accordance with anembodiment.

FIG. 7A includes a cross-sectional side view of a bearing in accordancewith an embodiment prior to engagement with a post.

FIG. 7B includes a top view of a bearing in accordance with anembodiment prior to engagement with a post.

FIG. 7C includes a cross-sectional side view of a bearing in accordancewith an embodiment after engagement with a post.

FIG. 7D includes a top view of a bearing in accordance with anembodiment after engagement with a post.

FIG. 8A includes a cross-sectional side view of a bearing in accordancewith an embodiment prior to engagement with a post.

FIG. 8B includes a top view of a bearing in accordance with anembodiment prior to engagement with a post.

FIG. 8C includes a cross-sectional side view of a bearing in accordancewith an embodiment after engagement with a post.

FIG. 8D includes a top view of a bearing in accordance with anembodiment after engagement with a post.

FIG. 9A includes a cross-sectional side view of a bearing in accordancewith an embodiment prior to engagement with a post.

FIG. 9B includes a top view of a bearing in accordance with anembodiment prior to engagement with a post.

FIG. 9C includes a cross-sectional side view of a bearing in accordancewith an embodiment after engagement with a post.

FIG. 9D includes a top view of a bearing in accordance with anembodiment after engagement with a post.

FIG. 10A includes a cross-sectional side view of a bearing in accordancewith an embodiment prior to engagement with a post.

FIG. 10B includes a top view of a bearing in accordance with anembodiment prior to engagement with a post.

FIG. 10C includes a cross-sectional side view of a bearing in accordancewith an embodiment after engagement with a post.

FIG. 10D includes a top view of a bearing in accordance with anembodiment after engagement with a post.

FIG. 11 includes a perspective view of a bearing in accordance with anembodiment.

FIG. 12A includes a perspective view of a bearing engaged with a post inaccordance with an embodiment.

FIG. 12B includes a top view of a bearing engaged with a post inaccordance with an embodiment.

FIG. 12C includes a cross-sectional side view of a bearing in accordancewith an embodiment.

FIG. 13A includes a perspective view of a bearing engaged with a post inaccordance with an embodiment.

FIG. 13B includes a top view of a bearing engaged with a post inaccordance with an embodiment.

FIG. 13C includes a cross-sectional side view of a bearing in accordancewith an embodiment.

FIG. 14A includes a top view of a bearing in accordance with anembodiment prior to engagement with a post.

FIG. 14B includes a top view of a bearing in accordance with anembodiment after engagement with a post.

FIG. 15 includes a top view of a bearing in accordance with analternative embodiment.

FIG. 16 includes a cross-sectional top view of a bearing including a lowfriction layer in accordance with an embodiment, taken along Line 16-16in FIG. 11.

FIG. 17 includes a perspective view of a locking mechanism in accordancewith an embodiment.

FIG. 18 includes a first side plan view of a locking mechanism inaccordance with an embodiment.

FIG. 19 includes a second side plan view of a locking mechanism inaccordance with an embodiment.

FIG. 20 includes a top view of a locking mechanism in accordance with anembodiment.

FIG. 21 includes a cross-sectional side view of a guide sleeve inaccordance with an embodiment, taken along line 21-21 of FIG. 3B.

FIG. 22 includes a side plan view of a cutout in accordance with anembodiment.

FIG. 23 includes a perspective view of a locking member in accordancewith an embodiment.

FIG. 24 includes a side plan view of a locking member in accordance withan embodiment.

FIG. 25 includes a top view of a locking member in accordance with anembodiment.

FIG. 26 includes a cross-sectional side view of a locking mechanism inaccordance with an embodiment, taken along Line 26-26 in FIG. 20.

FIG. 27A includes a first cross-sectional side view of a lockingmechanism in accordance with an embodiment, taken along Line 27-27 inFIG. 20.

FIG. 27B includes a second cross-sectional side view of a lockingmechanism in accordance with an embodiment, taken along Line 27-27 inFIG. 20.

FIG. 28 includes a cross-sectional side view of a locking mechanism inaccordance with an embodiment, taken along Line 27-27 in FIG. 20,including a central axis for the locking member and a central axis forthe locking mechanism.

FIG. 29 includes a side plan view of the central axes of FIG. 28according to an embodiment.

FIG. 30 includes a cross-sectional side view of a locking mechanism inaccordance with an embodiment, taken along Line 27-27 in FIG. 20,including a central axis for the locking member and a central axis forthe locking mechanism.

FIG. 31 includes a side plan view of the central axes of FIG. 30according to an embodiment.

FIG. 32 includes a side plan view of an actuating member in accordancewith an embodiment.

FIG. 33 includes a perspective view of an actuating member in accordancewith an embodiment.

FIG. 34 includes a chart of radial stiffness in accordance with anembodiment.

FIG. 35A includes a perspective view of a wave structure in accordancewith an embodiment.

FIG. 35B includes a side plan view of a wave structure in accordancewith an embodiment.

FIG. 35C includes a side plan view of a wave structure in accordancewith an embodiment.

FIG. 35D includes a cross sectional view of a wave structure as seenalong Line 34-34 in FIG. 34B, according to an embodiment.

FIG. 35E includes a cross sectional view of a wave structure as seenalong Line 34-34 in FIG. 34C, according to an embodiment.

FIG. 36A includes a perspective view of a wave structure in accordancewith an embodiment.

FIG. 36B includes a side plan view of a wave structure in accordancewith an embodiment.

FIG. 36C includes a side plan view of a wave structure in accordancewith an embodiment.

FIG. 37A includes a perspective view of a wave structure in accordancewith an embodiment.

FIG. 37B includes a side plan view of a wave structure in accordancewith an embodiment.

FIG. 37C includes a side plan view of a wave structure in accordancewith an embodiment.

FIG. 37D includes a cross sectional view of a wave structure as seenalong Line 36-36 in FIG. 36B, according to an embodiment.

FIG. 37E includes a cross sectional view of a wave structure as seenalong Line 36-36 in FIG. 36C, according to an embodiment.

FIG. 38A includes a cross sectional view of a wave structure inaccordance with an embodiment.

FIG. 38B includes a cross sectional view of a wave structure inaccordance with an embodiment.

FIG. 39A includes a perspective view of a wave structure in accordancewith an embodiment.

FIG. 39B includes a side plan view of a wave structure in accordancewith an embodiment.

FIG. 39C includes a side plan view of a wave structure in accordancewith an embodiment.

FIG. 39D includes an elevation view of a wave structure in accordancewith an embodiment.

FIG. 39E includes an elevation view of a wave structure in accordancewith an embodiment.

FIG. 40A includes a side plan view of a wave structure in accordancewith an embodiment.

FIG. 40B includes a side plan view of a wave structure in accordancewith an embodiment.

Skilled artisans appreciate that elements in the figures are illustratedfor simplicity and clarity and have not necessarily been drawn to scale.For example, the dimensions of some of the elements in the figures maybe exaggerated relative to other elements to help to improveunderstanding of embodiments of the invention.

DETAILED DESCRIPTION

The following description in combination with the figures is provided toassist in understanding the teachings disclosed herein. The followingdiscussion will focus on specific implementations and embodiments of theteachings. This focus is provided to assist in describing the teachingsand should not be interpreted as a limitation on the scope orapplicability of the teachings. However, other embodiments can be usedbased on the teachings as disclosed in this application.

As used herein to describe range of movement of the posts, the term“adjustment length” describes the maximum distance the posts cantranslate into and away from a seat back while maintaining lockableengagement therewith. In a particular aspect, the “adjustment length”can be defined as the length of the segment of the head restraint postthat is exposed from the seat back when the head restraint assembly isat its maximum height. In this sense, the “adjustment length” of theposts can be less than the entire axial length of the posts. Further, asdescribed herein, the posts can be locked at any position along theiradjustment length.

The terms “comprises,” “comprising,” “includes,” “including,” “has,”“having” or any other variation thereof, are intended to cover anon-exclusive inclusion. For example, a method, article, or apparatusthat comprises a list of features is not necessarily limited only tothose features but may include other features not expressly listed orinherent to such method, article, or apparatus. Further, unlessexpressly stated to the contrary, “or” refers to an inclusive-or and notto an exclusive-or. For example, a condition A or B is satisfied by anyone of the following: A is true (or present) and B is false (or notpresent), A is false (or not present) and B is true (or present), andboth A and B are true (or present).

Also, the use of “a” or “an” is employed to describe elements andcomponents described herein. This is done merely for convenience and togive a general sense of the scope of the invention. This descriptionshould be read to include one, at least one, or the singular as alsoincluding the plural, or vice versa, unless it is clear that it is meantotherwise. For example, when a single item is described herein, morethan one item may be used in place of a single item. Similarly, wheremore than one item is described herein, a single item may be substitutedfor that more than one item.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. The materials, methods, andexamples are illustrative only and not intended to be limiting. To theextent not described herein, many details regarding specific materialsand processing acts are conventional and may be found in textbooks andother sources within the head restraint arts.

The present head restraint assembly is adapted to provide consistentsliding resistance and adjustability. The concepts are better understoodin view of the embodiments described below that illustrate and do notlimit the scope of the present invention

Referring initially to FIG. 2, a vehicle seat 2 is partiallyillustrated. The seat 2 can include a seat bottom (not shown) that ismounted within a vehicle. The seat 2 can also include a seat back 4 thatis mounted to one of the seat bottom or the vehicle. The seat back 4 canfurther include a head restraint assembly 1. The head restraint assembly1 can be engaged with a top surface 6 of the seat back 4. The headrestraint assembly 1 can be adapted to translate relative to the seatback 4. In this regard, the head restraint assembly 1 can be adjusted toaccommodate passengers of various heights.

Referring to FIG. 1 through FIG. 3B, the head restraint assembly 1 cangenerally include a body (e.g., a head cushion) 2, a first post 100 anda second post 102 extending from the head cushion 2, a first guidesleeve 200 engaged with the first post 100, and a second guide sleeve202 engaged with the second post 102. The first guide sleeve 200 canfurther include a first bearing 300 having a first and second distalend, and a locking mechanism 400. Similarly, the second guide sleeve 202can further include a second bearing 300 having a first and seconddistal end. The first and second bearings 300, 302 can each have a firstend 306 and a second end 308, the second end 308 having substantiallythe same shape as the first end 306. The locking mechanism 400 can beengaged to the first end 306.

In a particular embodiment, the head cushion 2 can be made of a foamedpolymer material and can have an internal framework. The head cushion 2can further include an outer material selected to cover the foamedplastic, such as, for example, a vinyl, a fabric, a leather, or acombination thereof. The internal framework can comprise any rigidmaterial sufficient to support the head cushion 8. The internalframework can be formed from several axial members affixed together orfrom a single piece. Extending from the internal framework can be thefirst and second posts 100 and 102. The posts 100, 102 can be integralwith the framework or can be attached to the framework in any mannerrecognizable to one having ordinary skill in the art. For example, theposts 100, 102 can be welded to the framework. Alternatively, the posts100, 102 can be mechanically deformed to engage the framework (e.g., theposts 100, 102 being crimped or bent around the framework).Alternatively, the posts 100, 102 can be affixed to the framework by athreadable engagement, or other similar type fastener.

In a particular embodiment, the first and second posts 100, 102 canextend in a substantially parallel orientation from the head cushion 2.In a further embodiment, the first and second posts 100, 102 can extendfrom the head cushion 2 in a parallel fashion. As used herein,“substantially parallel” refers to a relative angle as formed betweentwo lines or planes of no greater than 10°, such as no greater than 5°,or even no greater than 1°. As used herein, “parallel” refers to arelative angle as formed between two lines or planes of no greater than0.1°.

The posts 100, 102 can have a diameter, D_(P), a circumference, C_(P),and a length, L_(P). In a particular embodiment, the posts 100, 102 canbe sized such that they are of equal or variable lengths. The posts 100,102 can be made from a material selected from metal, composite, polymer,ceramic, or any other material having sufficient rigidity and strengthto withstand both lateral and axial forces exhibited during vehicularoperation.

In a particular embodiment, at least a portion of the posts 100, 102 canbe formed of straight, cylindrical rods. In a more particularembodiment, the posts 100, 102 can have one or more radial bends 104therein. The radial bends 104 can offset the head cushion 2 from theseat back 4. In yet another embodiment, the posts 100, 102 can eachinclude an articulated joint to enable rotational adjustment of the headcushion 2 relative to the seat back 4. In this regard, the head cushion2 can be rotatably articulated around the top of the posts 100, 102. Thearticulated joint can be located within the head cushion 2.

In a particular aspect, at least one of the posts 100, 102 can have astop feature 108 (FIG. 4). The stop feature 108 can be adapted to engagewith a complementary locking mechanism (described below) affixed to theseat back 4. In a particular aspect, the stop feature 108 can be aradial groove or channel extending at least partially around thecircumference, C_(P).

In an embodiment, the posts 100, 102 can have a smooth outer surfacefree of external indentations, external notches, grooves, and/orchannels. The posts 100, 102 can have an adjustment length, L_(A), asmeasured by the length of the segment of the posts 100, 102 that isexposed from the seat back 4 when the head restraint assembly 1 is atits maximum height.

In this regard, the adjustment length, L_(A), can be increased bycorrespondingly increasing the length of L_(P). In another aspect, L_(A)can be increased by repositioning the stop feature 108 closer to theleading end 106 of the posts 100, 102.

In a particular embodiment, a ratio of L_(P):L_(A) can be no greaterthan 4.0, such as no greater than 3.5, no greater than 3.0, no greaterthan 2.5, no greater than 2.0, no greater than 1.5 no greater than 1.25,or even no greater than 1.1. The ratio of L_(P):L_(A) can be greaterthan 1.0, such as greater than 1.1, greater than 1.2, greater than 1.3,greater than 1.4, greater than 1.5, greater than 1.6, greater than 1.7,greater than 1.8, greater than 1.9, or even greater than 2.0.Additionally, the value for the ratio of L_(P):L_(A) can be selectedfrom a value as within the range defined above.

The stop feature 108 can be separated from the leading end 106 of theposts 100, 102 a length, L_(SF), as measured between the leading end 106and the nearest surface of the stop feature 108. In a particular aspect,a ratio of L_(P):L_(SF) can be no greater than 100, such as no greaterthan 75, no greater than 50, no greater than 25, or even no greater than10. The ratio of L_(P):L_(SF) can be no less than 0.5, such as no lessthan 1, no less than 5, no less than 10, no less than 20, no less than30, no less than 40, or even no less than 50. Additionally, the valuefor the ratio of L_(P):L_(SF) can be selected from a value as within therange defined above.

In a particular embodiment the guide sleeves 200, 202 can additionallyinclude a stop feature 204, which is adapted to engage with the stopfeature 108 of the posts 100, 102. The stop features 108, 204 can beadapted to prevent the posts 100, 102 from disengaging from the guidesleeve guides 200, 202. The stop features 108, 204 can comprise anyfeature as would be recognizable to one having ordinary skill in the artfor preventing axial disengagement of two substantially concentriccomponents.

For example, as illustrated in FIG. 4, one of the stop features 108, 204can comprise a radial projection 206 adapted to engage with acorresponding recess 208 in the other stop feature 108, 204. In aparticular aspect, the radial projection 206 can be spring biasedtowards the corresponding recess 208. In this regard, the radialprojection 206 can engage with the corresponding recess 208 and canprevent the posts 100, 102 from disengaging from the guide sleeves 200,202.

Alternatively, the stop features 108, 204 can comprise a molly adaptedto be engageable onto one of the posts 100, 102. The molly can be springbiased such that after insertion of the posts 100, 102 through the guidesleeves 200, 202, the molly expands or extends radially outward beyondthe guide sleeves 200, 202. This expansion or extension can anchor thestop features 108, 204 and prevent the posts 100, 102 from disengagingfrom the guide sleeves 200, 202.

Referring again to FIG. 1 through FIG. 3, the first and second bearings300, 302 can be adapted to engage around each of the first and secondposts 100, 102. In particular embodiments, the posts 100, 102 and thebearings 300, 302 can have a poka yoke or other mechanism to assist inaligning the posts 100, 102 within the bearings 300, 302. As usedherein, “poka yoke” refers to a complementary shaping feature located oneach of the posts 100, 102 and the bearings 300, 302 to assist inpreventing unintended movement between the parts and to facilitateeasier assembly. For example, the poka yoke may comprise a tongue andgroove extending along an axial length of the posts 100, 102 and thebearings 300, 302. In particular embodiments, the poka yoke can includeinterlocking ribs formed on one of the posts 100, 102 and bearings 300,302 and channels on the other of the posts 100, 102 and bearings 300,302, pins and grooves, or any other complementary engagement structureallowing for a more precise and defect-free assembling of components.

Referring now to FIG. 5 and FIG. 6, in a particular embodiment, thebearings 300, 302 can be formed from a strip 304 of resilient material,e.g. spring steel, having opposite axial ends 306, 308 andcircumferential ends 310, 312. The strip 304 can include an undeformedportion 316 and at least one row of wave structures 318. The wavestructures 318 can be press-formed, e.g. stamped, into the strip 304. Asused herein, “undeformed portion” can refer to an annular sidewall ofthe bearing(s) from which wave structure(s) protrude. More particularly,the “undeformed portion” can include a portion of the strip 304 that isnot deformed other than during forming of an annular, or cylindrical,shape, e.g., the undeformed portion is devoid of wave structure(s). Asused herein, the “undeformed portion” can include an annular sidewall ofthe bearing(s) defining at least one of an inner diameter or an outerdiameter of the bearing(s).

In a particular embodiment, illustrated in FIG. 7A through 7D, each wavestructure 318 can be substantially identical in size and shape to permita more even radial compression around the circumference of the bearings300, 302. In a particular embodiment, the wave structures 318 can have alength, L_(WS), extending at least partially between the axial ends 306,308. In another embodiment, the wave structures 318 can extend parallelwith the axial ends 306, 308. In a further embodiment, the wavestructures 318 can extend in any angular orientation relative the axialends 306, 308.

For example, as illustrated in FIG. 8A through 8D, the wave structures318 can be formed parallel to the ends 306, 308. In a furtherembodiment, each wave structure 318 can have unique or dissimilarcharacteristics. In a particular aspect, the wave structures 318 can besubstantially rectangular cuboids. In another aspect, as illustrated inFIG. 9A through 9D, the wave structures 318 can be substantiallypyramidal. In a further aspect, as illustrated in FIG. 10A through FIG.10D, the wave structures 318 can be hemispherical dimples. In yetanother aspect, the wave structures 318 can be conical. Additionally,the wave structures 318 can be formed to have any other projectingsurface capable of engaging an inner post 100, 102.

In a particular embodiment, the wave structures 318 can have a uniformprojecting distance, D_(WP). In an alternative embodiment, the wavestructures 318 can have varying projecting distances, D_(WP).

In a particular aspect, there can be a number of wave structures,N_(WS), located peripherally around the bearings 300, 302. N_(WS) can beat least 3, such as N_(WS) is at least 4, at least 5, at least 6, atleast 7, at least 8, at least 9, at least 10, at least 11, at least 12,at least 13, at least 14, at least 15, or even at least 16. N_(WS) canbe no greater than 40, such as no greater than 35, not greater than 30,no greater than 25, no greater than 20, no greater than 15, or even notgreater than 10. N_(WS) can also be within a range between and includingany of the above described values.

Further, each wave structure 318 can include a number of rows (extendingcircumferentially), N_(SWS), of smaller wave structures 318. N_(SWS) canbe at least 2, such as at least 3, or even at least 4. N_(SWS) can be nogreater than 6, such as not greater than 5, not greater than 4, or evennot greater than 3. N_(SWS) can also be within a range between andincluding any of the above described values.

In this aspect, it should be understood that all reference to wavestructures 318 herein can include either a single wave structure 318 orany number of wave structures, N_(SWS), within the range defined above.It should be further understood that each wave structure 318 can haveidentical or varying dimensional and physical characteristics. In aparticular aspect, the wave structures 318 can vary in shape anddimensional size around the circumference of the bearings 300, 302. Inanother aspect, all of the wave structures 318 can be substantiallyidentical.

Moreover, the wave structures 318 can be disposed of along the strip 304rectilinearly, as illustrated in FIG. 5, or non-rectilinearly, asillustrated in FIG. 11. In the latter embodiment, the wave structures318 can be staggered around the strip 304 such that the wave structures318 do not align axially. In this regard, the wave structures 318 can beadapted to provide a substantially even radially inward compressiveforce against the posts 100, 102 disposed of within the bearings 300,302. When viewed along the length of the bearings 300, 302, each bearing300, 302 can have at least 3 wave structures, such as at least 4 wavestructures, at least 5 wave structures, or even at least 6 wavestructures circumferentially disposed around the bearing 300, 302.

As illustrated in FIG. 12A through FIG. 12C, in a particular embodiment,the bearings 300, 302 can be adapted to receive an angled post 100, 102therein. The wave structures 318 can have variable projecting distances,D_(WP), to accommodate for this angular engagement. In a furtherembodiment, illustrated in FIG. 13A through FIG. 13C, the bearings 300,302 can be adapted to receive off-centered posts 100, 102 that are notconcentrically aligned with the bearings 300,302. In this regard, thewave structures 318 can be formed such that the wave structures 318 aresubstantially identical in the axial direction but increase or decreasecircumferentially.

In a particular embodiment, to form the bearings 300, 302, the strip 304can be curved to form an annular ring by bringing circumferential ends310, 312 towards one another. The resulting bearings 300, 302 can eachhave a central axis 322, and a functional circumference, C_(F), asmeasured circumferentially by a best fit circle tangent to an innermostportion 320 of the wave structures. In a particular embodiment, thestrip 304 can be curved to form an overlap between ends 310, 312 toincrease the dimensional range that the bearings 300, 302 canaccommodate.

As illustrated in FIG. 14A, in a particular aspect, the bearings 300,302 can have a functional inner diameter, ID_(F), as measured betweenthe inner surface 320 of two opposite wave structures 318, 318 prior toengagement with the posts 100, 102. The posts 100, 102 can comprise anouter diameter, D_(P). In a particular aspect, a ratio of D_(P):ID_(F)can be no greater than 1.5, such as no greater than 1.45, no greaterthan 1.4, no greater than 1.35, no greater than 1.3, no greater than1.25, no greater than 1.2, no greater than 1.15, no greater than 1.1, nogreater than 1.05, or even no greater than 1.025. The ratio ofD_(P):ID_(F) can be no less than 1.005, such as no less than 1.01, noless than 1.02, no less than 1.03, no less than 1.04, no less than 1.05,no less than 1.06, no less than 1.07, no less than 1.08, no less than1.09, or even no less than 1.1. Additionally, the ratio of D_(P):ID_(F)can also be within a range between and including any of the ratio valuesdescribed above. In a particular aspect, as the ratio of D_(P):ID_(F)increases, the wave structures 318 can provide a greater radial forceagainst the posts 100, 102.

The bearings 300, 302 can further comprise a total circumference, C_(T),which can be measured by a best fit circle along the inner surface 336of the undeformed portion 316 of the bearings 300, 302 prior toinsertion of the posts 100, 102 therein.

In a particular embodiment, the bearings 300, 302 can have an initialgap 314 between ends 310, 312. The initial gap 314 can be defined as thegap between the ends 310, 312 prior to insertion of the posts 100, 102into the bearings 200, 203. The initial gap 314 can have an initialwidth, W_(GI), as measured perpendicular between ends 310, 312. A ratioof W_(GI):C_(T) can be no greater than 0.30, such as no greater than0.25, no greater than 0.20, no greater than 0.15, no greater than 0.10,less than 0.05, or even less than 0.04. The ratio of W_(GI):C_(T) can beno less than 0.01, such as no less than 0.02, no less than 0.03, no lessthan 0.04, no less than 0.05, no less than 0.06, no less than 0.07, noless than 0.08, no less than 0.09, or even no less than 0.10. The ratioof W_(GI):C_(T) can also be within a range between and including any ofthe ratio values described above. As used herein, C_(T) can beunderstood to include both the circumferential length of the innersurface 336 of the bearing 300, 302 and the length, W_(GI), of the gap314.

Further, in a particular embodiment, as illustrated in FIG. 14B, uponinsertion of the posts 100, 102 into the bearings 300, 302, the widthbetween the ends 310, 312 can increase to form an operational gap 338having a width, W_(GO). A ratio of W_(GO):W_(GO) can be no less than0.01, such as no less than 0.02, no less than 0.03, no less than 0.04,no less than 0.05, no less than 0.10, no less than 0.15, no less than0.20, no less than 0.25, no less than 0.30, no less than 0.35, or evenno less than 0.40. The ratio of W_(GO):W_(GI) is no greater than 0.75,such as no greater than 0.70, no greater than 0.65, no greater than0.60, no greater than 0.55, no greater than 0.50, no greater than 0.45,no greater than 0.40, no greater than 0.35, no greater than 0.30, nogreater than 0.25, no greater than 0.20, no greater than 0.15, nogreater than 0.10, or even no greater than 0.05. The ratio ofW_(GO):W_(GI) can also be within a range between and including any ofthe ratio values described above.

In a further embodiment, the bearings 300, 302 can have an operationalinner diameter, ID_(O), which can be measured between the inner surface320 of two opposite wave structures 318, 318 after engagement of thebearings 300, 302 with the posts 100, 102. In a particular aspect, aratio of ID_(O):ID_(F) can be no less than 1.05, such as no less than1.10, no less than 1.15, no less than 1.20, no less than 1.25, no lessthan 1.30, no less than 1.35, no less than 1.40, no less than 1.45, noless than 1.50, no less than 1.55, or even no less than 1.60. The ratioof ID_(O):ID_(F) can be no greater than 2.00, such as no greater than1.75, no greater than 1.50, no greater than 1.25, or even no greaterthan 1.10. The ratio of ID_(O):ID_(F) can also be within a range betweenand including any of the ratio values described above.

In a particular aspect, the bearings 300, 302 can have a functionalcircumference, as measured by a best fit circle along the undeformedportion 316 of the bearings 300, 302 after insertion of the posts 100,102 therein. A ratio of C_(T):C_(F) can be at least 1.025, at least1.05, at least 1.1, at least 1.2, at least 1.3, at least 1.4, at least1.5, at least 1.75, or even at least 2.0. The ratio of C_(T):C_(F) canbe less than 5, less than 4, less than 3, less than 2, or even less than1.5. The ratio of C_(T):C_(F) can also be within a range between andincluding any of the ratio values described above.

In a particular aspect each wave structure 318 can have an arcuatecross-section with a radius of curvature, R_(WS), measuredperpendicularly from the undeformed portion 316 of the strip 304 to theinner surface 320 of the wave structure 318. In cases where the wavestructures 318 have varying curvatures (e.g., parabolic shaped) theR_(WS) is measured according to the best fit circle within the wavestructure 318. The bearings 300, 302 can also have a body radius, R_(B),which can be measured perpendicular from the central axis 322 of thebearings 300, 302 to the undeformed portion 316.

Further, in a particular aspect R_(WS) can be no greater than 0.50R_(B), such as no greater than 0.45 R_(B), no greater than 0.40 R_(B),no greater than 0.35 R_(B), no greater than 0.30 R_(B), no greater than0.25 R_(B), no greater than 0.20 R_(B), no greater than 0.15 R_(B), nogreater than 0.10 R_(B), or even no greater than 0.05 R_(B).Furthermore, R_(WS) can be at least 0.01 R_(B), such as at least 0.02R_(B), at least 0.03 R_(B), at least 0.04 R_(B), at least 0.05 R_(B), atleast 0.10 R_(B), at least 0.15 R_(B), or even at least 0.20 R_(B). Therelationship of R_(B) and R_(WS) can also be within a range between andincluding any of the ratio values described above.

In a particular embodiment, illustrated in FIG. 15, the bearings 300,302 can include only the strip of material 304. In another embodiment,as illustrated in FIG. 16, the bearings 300, 302 can further include alow friction layer 324 which can provide enhanced slidingcharacteristics with the posts 100, 102. The low friction layer 324 cancomprise materials including, for example, a polymer, such as aplyketone, polyaramid, a polyimide, a polytherimide, a polyphenylenesulfide, a polyetherslfone, a polysulfone, a polypheylene sulfone, apolyamideimide, ultra high molecular weight polyethylene, afluoropolymer, a polyamide, a polybenzimidazole, or any combinationthereof.

In an example, the polymer material includes a polyketone, a polyaramid,a polyimide, a polyetherimide, a polyamideimide, a polyphenylenesulfide, a polyphenylene sulfone, a fluoropolymer, a polybenzimidazole,a derivation thereof, or a combination thereof. In a particular example,the thermoplastic material includes a polymer, such as a polyketone, athermoplastic polyimide, a polyetherimide, a polyphenylene sulfide, apolyether sulfone, a polysulfone, a polyamideimide, a derivativethereof, or a combination thereof. In a further example, the materialincludes polyketone, such as polyether ether ketone (PEEK), polyetherketone, polyether ketone ketone, polyether ketone ether ketone, aderivative thereof, or a combination thereof. In an additional example,the thermoplastic polymer may be ultra high molecular weightpolyethylene.

An example fluoropolymer includes fluorinated ethylene propylene (FEP),PTFE, polyvinylidene fluoride (PVDF), perfluoroalkoxy (PFA), aterpolymer of tetrafluoroethylene, hexafluoropropylene, and vinylidenefluoride (THV), polychlorotrifluoroethylene (PCTFE), ethylenetetrafluoroethylene copolymer (ETFE), ethylene chlorotrifluoroethylenecopolymer (ECTFE), or any combination thereof. Fluoropolymers are usedaccording to particular embodiments.

Additionally, the bearings 300, 302 can include lubrication to furtherenhance sliding characteristics between the bearing 300, 202 and theposts 100, 102. Exemplary lubricants can include molybdenum disulfide,tungsten disulfide, graphite, grapheme, expanded graphite, boronnitrade, talc, calcium fluoride, or any combination thereof.Additionally, the lubricant can comprise alumina, silica, titaniumdioxide, calcium fluoride, boron nitride, mica, Wollastonite, siliconcarbide, silicon nitride, zirconia, carbon black, pigments, or anycombination thereof.

A combination of the spring characteristics of the bearing 300, 302 withthe low friction/lubrication characteristics of the low friction layer324 can provide a low friction sliding surface.

In a particular embodiment, the strip 304 can have a thickness, T_(S),and the low friction layer 324 can have a thickness, T_(LFL). A ratio ofT_(S):T_(LFL) can be at least 1, such as at least 1.5, at least 2, atleast 2.5, at least 3, at least 3.5, at least 4, at least 4.5, or evenat least 5. The ratio of T_(S):T_(LFL) can be no greater than 50, suchas no greater than 40, no greater than 30, no greater than 20, or evenno greater than 10. Additionally, the ratio of T_(S):T_(LFL) can bewithin a range between and including any of the ratio values describedabove.

In a particular embodiment, the low friction layer 324 can have athickness of no less than 0.01 mm, such as no less than 0.05 mm, no lessthan 0.1 mm, no less than 0.2 mm, no less than 0.3 mm, no less than 0.4mm, no less than 0.5 mm, no less than 0.6 mm, no less than 0.7 mm, noless than 0.8 mm, no less than 0.9 mm, or even no less than 1 mm. Thethickness of the low friction layer 324 can be no greater than 10 mm,such as no greater than 9 mm, no greater than 8 mm, no greater than 7mm, no greater than 6 mm, no greater than 5 mm, no greater than 4 mm, nogreater than 3 mm, no greater than 2 mm, or even no greater than 1 mm.Additionally, the thickness of the low friction layer 324 can also bewithin a range between and including any of the ratio values describedabove.

In some embodiments, the low friction layer 324 can be laminated onto aninner surface 336 of the bearings 300, 302. In other embodiments, thelow friction layer 224 can be affixed to the inner surface 336 of thebearings 300, 302 by chemical process. In yet another embodiment, thelow friction layer 224 can be affixed to the inner surface 336 of thebearings 300, 302 by mechanical deformation. In still other embodiments,the low friction layer 324 can be attached to the bearing 300, 302 byany method known in the art. After the low friction layer 324 isattached to the strip 304 of the bearing 300, 302 the resultingstructure can be stamped, e.g. pressed using a suitably shaped mold,rotary wave forming, etc., to form the wave structures 318. Thus, thewave structures 318 can be formed from both the strip of resilientmaterial 304 and from the low friction layer 324.

In a particular embodiment, the bearings 300, 302 can reduce frictionalresistance of the posts 100, 102 within the guide sleeves 200, 202,allowing for easier translation of the head restraint assembly 1relative the seat back 4. In another embodiment, the bearings 300, 302can provide a zero-clearance fit between the guide sleeves 200, 202 andthe posts 100, 102. In yet a further embodiment, the bearings 300, 302can eliminate or substantially reduce squeaking of the assembly 1 whenthe posts 100, 102 are translated relative the guide sleeves 200, 202.

In a particular embodiment, the bearings 300, 302 can be adapted toapply a radially inward force against the posts 100, 102 so as to form a“zero-clearance” fit therebetween. In this regard, a zero-clearance fitcan be formed between the bearings 300, 302 and the posts 100, 102. Asused herein, the term “zero-clearance” is defined by an engagementbetween a bearing and a post substantially devoid of perceptible radialplay or movement upon application of a force against the bearingperpendicular to the central axis of the bearing, while holding the postinstalled therein stationary at 0 degrees, 45 degrees, 90 degrees, 135degrees, 180 degrees, 225 degrees, and 270 degrees positions.

In a particular aspect, it is desirable for the bearings 300, 302 toprovide a high degree of radial stiffness to the posts 100, 102 whilesimultaneously permitting low axial sliding forces of the posts 100, 102within the bearings 300, 302. In this regard, the head restraintassembly 1 can support high normal loads while simultaneously permittingtranslation of the posts 100, 102 within the bearings 300, 302 uponapplication of a minimal axial load.

In a particular embodiment, the bearings 300, 302 can form aninterference fit with the posts 100, 102 such that the bearings 300, 302can provide the posts 100, 102 with a radial stiffness of no less thanabout 2,000 N/mm while simultaneously allowing the posts to translateupon an axial sliding force of no greater than about 30 N. In furtherembodiments, the bearings 300, 302 can provide the posts with a radialstiffness of no less than about 2,250 N/mm, no less than about 2,500N/mm, no less than about 2,750 N/mm, no less than about 3,000 N/mm, noless than about 3,500 N/mm, or no less than about 4,000 N/mm. Radialstiffness of the bearings 300, 302 can be determined at anytime afterinsertion of the posts 100, 102 in the bearings 300, 302. For example,after one of the posts 100, 102 has been inserted into one of thebearings 300, 302 as previously described, the radial stiffness of thepost 100, 102 and bearing 300, 302 preassembly can be determined byfixing one of the post 100, 102 or bearings 300, 302 and applying aperpendicular normal force to the other one of the post 100, 102 orbearings 300, 302. The force necessary to affect radial movement of oneof the posts 100, 102 or bearings 300, 302 can be determinative of theradial stiffness of the bearings 300, 302.

In particular embodiments, the bearings 300, 302 can provide a desiredradial stiffness while simultaneously permitting axial translation ofthe posts 100, 102 therein upon application of an axial sliding force ofno greater than about 29 N, no greater than about 28 N, no greater thanabout 27 N, no greater than about 26 N, no greater than about 25 N, nogreater than about 24 N, no greater than about 23 N, no greater thanabout 22 N, no greater than about 21 N, no greater than about 20 N, nogreater than about 19 N, no greater than about 18 N, no greater thanabout 17 N, no greater than about 16 N, no greater than about 15 N, nogreater than about 14 N, no greater than about 13 N. In this regard, thebearings 300, 302 can provide an affective resistance to radial movementwhile permitting axial translation of the posts 100, 102 uponapplication of a minimal longitudinal force.

In a particular aspect, the zero-clearance between the bearings 300, 302and the posts 100, 102 can be generated by the wave structures 318 ofthe bearings 300, 302 extending radially inward from the bearing 300,302 walls and compressing against the posts 100, 102 along a best fitcircle tangent to the inner wave surface 320. In a particularembodiment, each of the wave surfaces 320 can define a point contactlocation adapted to contact with the posts 100, 102 along the best fitcircle. In another embodiment, the wave surfaces 320 can define a planarportion adapted to provide an area contact location between the posts100, 102 and the bearings 300, 302. In this regard, the contact betweenthe posts 100, 102 and the bearings 300, 302 can be either point contactor area contact.

In particular embodiments, each of the wave structures 318 can have abest fit circle having an initial diameter, D_(I), as measured by thediameter of the best fit circle prior to installation of the posts 100,102, and an operational diameter, D_(O), as measured by the diameter ofthe best fit circle after installation of the posts 100, 102 therein. Ascontemplated herein, a zero clearance fit between the bearings 300, 302and the posts 100, 102 can require that D_(O) be greater than D_(I). Inthis regard, a ratio of D_(I):D_(O) can be no greater than 0.999, nogreater than 0.995, no greater than 0.990, no greater than 0.985, nogreater than 0.980, no greater than 0.975, no greater than 0.970, nogreater than 0.950, no greater than 0.925, no greater than 0.900. Theratio of D_(I):D_(O) can be no less than 0.4, no less than 0.5, no lessthan 0.6, no less than 0.7, no less than 0.8, no less than 0.9, no lessthan 0.95, no less than 0.96, no less than 0.97, no less than 0.98, noless than 0.99. Moreover, the ratio of D_(O):D_(I) can be within a rangebetween and including any of the ratio values described above, such as,for example, between 0.95 and 0.99.

In a particular aspect, the ratio between D_(I):D_(O) can be adjusted byselection of posts 100, 102 having a desirable outer diameter, D_(P). AsD_(P) is increased relative to D_(O), the resulting D_(I) can increaseto affect the relative zero clearance fit between the posts 100, 102 andthe bearings 300, 302.

In further embodiments, at least one of the bearings 300, 302 of theguide sleeves 200, 202 can have a bi-modal radial stiffness profile, aswill be described in greater detail below. In yet other embodiments,both of the bearings 300, 302 can have a bi-modal radial stiffnessprofile.

In such a manner, the bearings 300, 302 can have an initial unassembledradial stiffness as measured prior to insertion of the posts 100, 102therein, and an assembled radial stiffness as measured after insertionof the posts 100, 102 therein. In particular embodiments, the bearings300, 302 can be formed such that the assembled radial stiffness isdifferent than the initial unassembled radial stiffness.

For example, as shown in FIG. 34, the bearing(s) can have an initialunassembled radial stiffness (shown at line section 600) prior to thepost(s) being inserted into the bearing(s). The bearing(s) can have anassembled radial stiffness (shown at line section 602) as measured afterinsertion of the post(s) into the bearing(s). During insertion of thepost(s), the radial stiffness profile of the bearing(s) can increase, asseen at transition phase 604. It should be understood that the radialstiffness profile of the bearing(s) as seen at transition phase 604 ismerely illustrative and can have any contour (e.g., arcuate, linear,etc.), duration, and/or slope. Accordingly, the transition phase 604 canbe affected by any number of parameters, such as, for example, thematerial selection of the bearing(s), the geometric shape andorientation of the features herein described, and the forces used duringassembly.

The bi-modal radial stiffness profile shown in FIG. 34 can permitinsertion of the post(s) into the bearing(s) upon application of a lowaxial force (e.g., less than about 100 N, such as less than about 90 N,less than about 80 N, or even less than about 75 N), whilesimultaneously permitting the bearing(s) to exhibit a relatively highassembled radial stiffness (e.g., no less than about 1000 N/mm, such asno less than about 1500 N/mm, or even no less than about 2000 N/mm).

In this regard, in particular embodiments, the bearing(s) can have anassembled radial stiffness of no less than about 1,000 N/mm whilerequiring an initial assembly force of no greater than about 100 N. Infurther embodiments, the bearing(s) can have an assembled radialstiffness of no less than about 1100 N/mm, such as no less than about1200 N/mm, no less than about 1300 N/mm, no less than about 1500 N/mm,no less than about 1700 N/mm, no less than about 2000 N/mm, no less thanabout 2100 N/mm, no less than about 2200 N/mm, no less than about 2300N/mm, no less than about 2400 N/mm, no less than about 2500 N/mm, noless than about 3000 N/mm, no less than about 3500 N/mm, or even no lessthan about 4000 N/mm. In yet other embodiments, the bearing(s) can havean assembled radial stiffness of no greater than about 7500 N/mm, suchas no greater than about 7000 N/mm, no greater than about 6500 N/mm, nogreater than about 6000 N/mm, no greater than about 5500 N/mm, or evenno greater than about 5000 N/mm. Moreover, the assembled radialstiffness of the bearing(s) can also be within a range between andincluding any of the values described above, such as, for example,between about 4500 N/mm and about 4800 N/mm.

In particular embodiments the bearing(s) can be adapted to have anassembled radial stiffness within the range described above whilesimultaneously having an assembly force of no greater than about 100 N,such as no greater than about 95 N, no greater than about 90 N, nogreater than about 85 N, no greater than about 80 N, or even no greaterthan about 75 N.

In certain embodiments, the bearing(s) can have a bi-modal stiffnessprofile as a result of a bi-modal wave structure. In this regard, atleast one of the wave structures of at least one of the bearings canhave a bi-modal radial stiffness profile with an initial unassembledradial stiffness and an assembled radial stiffness.

In further embodiments, at least two of the wave structures can have abi-modal radial stiffness profile, such as at least three wavestructures, at least four wave structures, or even at least five wavestructures. In another embodiment, every wave structure on the at leastone bearing can have a bi-modal radial stiffness configuration. In yetfurther embodiments, the wave structures can have different bi-modalradial stiffness configurations, such as, for example, a unique bi-modalradial stiffness configuration for each wave structure, such that no twowave structures have the same bi-modal radial stiffness profile.

Bi-modal radial stiffness of at least one of the bearings or wavestructures can provide at least three advantages. First, a tighterradial fit can be achieved between the bearings and the posts withoutdamaging the bearings or posts. Second, the assembly forces can bereduced, permitting faster and easier assembly of the posts into thebearings. Third, particle generation caused by frictional sliding duringinsertion of the posts into the bearing can be minimized by reducing thenecessary axial forces as compared to an assembly without a bi-modalradial stiffness configuration.

In particular embodiments (e.g., those seen in FIGS. 35A to 40B), atleast one of the wave structures 318 of at least one of the bearings300, 302 can comprise a sizing feature 606. The sizing feature 606 cancomprise, for example, an aperture 608 extending through at least aportion of the at least one wave structure 318 (shown in FIGS. 35A to37E and 39A to 39E), a portion of the wave structure 318 having areduced thickness 610 (shown in FIGS. 38A and 38B), a dimpled section612 (shown in FIGS. 40A and 40B), or any combination thereof.

In certain embodiments, the sizing feature of the at least one wavestructure can cause the at least one bearing to have an initial innerdiameter, D_(I), as measured along a best fit circle tangent to theinnermost portions of the wave structures before the posts are insertedtherein. The sizing feature can further permit the bearing to have anoperational diameter, D_(O), as measured along a best fit circle tangentto the innermost portion of the wave structures after the post areinserted therein. A ratio of D_(O):D_(I) can be no less than 1.0, suchas no less than about 1.01, no less than about 1.02, no less than about1.03, no less than about 1.04, no less than about 1.05, or even no lessthan about 1.10. Moreover, in particular embodiments, the ratio ofD_(O):D_(I) can be no greater than about 2.0, such as no greater thanabout 1.9, no greater than about 1.8, no greater than about 1.7, or evenno greater than about 1.6. The ratio of D_(O):D_(I) can also be within arange of between and including any of the above described values, suchas, for example, between about 1.05 and about 1.10.

Referring now to FIGS. 35A through 36C, in a particular embodiment, atleast one of the wave structure 318 can include an aperture 608. In moreparticular embodiments, the aperture 608 can be positioned at leastpartially on an inner surface 614 of the at least one wave structure318.

The aperture 608 can define any shape when viewed from the inner surface614 of the wave structure 318, such as, for example, a generallypolygonal opening, a generally ellipsoidal opening, or a combinationthereof. In particular embodiments, the aperture 608 can be ovular(e.g., FIGS. 36A through 36C). In other embodiments, the aperture 608can be pinched (e.g., FIGS. 35A through 35E) in that the ends 618 aretapered.

FIGS. 35A, 35B, and 35D, show one embodiment of the wave structure 318in the initially unassembled state (i.e., prior to insertion of theposts into the bearings). In this regard, the aperture 608 is in theopen position. In the open position the radial stiffness of the wavestructure 318 is reduced (i.e., less than the assembled radial stiffnessof the wave structure 318) to allow for easier insertion of the postsinto the bearings. In the preassembled state, as shown, (i.e., prior topost insertion) the aperture 608 can extend at least partially along thewidth of the wave structure 318. The aperture 608 can have a maximumwidth, W_(A), as measured by the greatest distance the aperture 608extends perpendicular to the length of the wave structure 318.

During insertion of the post into the bearing, the aperture 608 can atleast partially close, thereby, enhancing the radial stiffness of thewave structure 318.

FIGS. 35C and 35E show the wave structure 318 in the assembled state(i.e., after insertion of the posts). It should be understood that inFIGS. 35C and 35E, the apertures 608 are shown exaggerated (i.e.,slightly open) in the assembled state and are not drawn to scale. Inpractice, the apertures 608 may fully close in the assembled state so asto reveal a seemingly continuous inner surface 614 devoid of openingstherein.

In other embodiments, the apertures 608 may substantially close in theassembled state such that a small opening remains along the innersurface 614 of the wave structure 318.

In the assembled state (e.g., FIGS. 35C and 35E), a radially innermostsurface 614 of the wave structure 318 can act as a parabolic arch,transferring the radial force provided by the posts along a side surface616 of the wave structure 318 to the undeformed section 316 of thebearing. Conversely, in the preassembled state, the wave structure 318is devoid of a continuous parabolic arch, subjecting the wave structure318 to deflect to the closed, or partially closed, assembled statewithout transferring significant forces to the undeformed section 316.In such a manner, minimal forces can be transferred to the undeformedsection 316 of the wave structure 318 during insertion of the posts intothe bearings.

FIGS. 36A and 36B show another embodiment of the wave structure 318 inthe initially unassembled state (i.e., prior to insertion of the posts).In this regard, the aperture 608 is in the open position. In the openposition, the radial stiffness of the wave structure 318 is reduced toallow for easier insertion of the posts into the bearings. In thepreassembled state, as shown, (i.e., prior to post insertion) theaperture 608 can extend at least partially along the length of the wavestructure 318. During insertion of the post 100, 102 into the bearing300, 302, the aperture 608 can at least partially close, thereby,enhancing stiffness of the wave structure 318.

FIG. 36C shows the wave structure 318 of FIGS. 36A and 36B in theassembled state (i.e., after insertion of the posts into the bearings).It should be understood that in FIG. 36C, the aperture 608 is shownexaggerated (i.e., slightly open) in the assembled state and is notdrawn to scale. In practice, the aperture 608 may fully close in theassembled state so as to reveal a continuous inner surface 614 devoid ofany opening therein.

In other embodiments, the aperture 608 may substantially close in theassembled state such that a small opening remains along the innersurface 614 of the wave structure 318.

In the assembled state (e.g., FIG. 36C), a radially innermost surface614 of the wave structure 318 can act as a parabolic arch, transferringthe radial force provided by the posts along a side surface 616 of thewave structure 318 to the undeformed section 316 of the bearing.Conversely, in the preassembled state, the wave structure 318 is devoidof a continuous parabolic arch, subjecting the wave structure 318 todeflect to the closed, or partially closed, assembled state withouttransferring significant forces to the undeformed section 316. In such amanner, minimal forces can be transferred to the undeformed section 316of the wave structure 318 during insertion of the posts into thebearings.

FIGS. 37A, 37B, and 37D show a further embodiment of the wave structure318 in the initially unassembled state (i.e., prior to insertion of theposts into the bearings). In this regard, the apertures 608 are in theopen position. In this position the radial stiffness of the wavestructure 318 is reduced to allow for easier insertion of the posts intothe bearings. In the preassembled state, as shown, (i.e., prior to postinsertion into the bearing) the apertures 608 can extend at leastpartially along the width of the wave structure 318. During insertion ofthe post into the bearing, the apertures 608 can at least partiallyclose, thereby, enhancing stiffness of the wave structure 318.

FIGS. 37C and 37E show the wave structure 318 of FIGS. 37A, 37B, and 37Din the assembled state (i.e., after insertion of the posts into thebearings). It should be understood that in FIGS. 37C and 37E, theapertures 608 are shown exaggerated (i.e., slightly open) in theassembled state and are not drawn to scale. In practice, the apertures608 may fully close in the assembled state so as to reveal a continuousinner surface 614 devoid of any opening therein.

In other embodiments, the apertures 608 may substantially close in theassembled state such that small opening remain along the inner surface614 of the wave structure 318.

In the assembled state (e.g., FIGS. 37C and 37E), a radially innermostsurface 614 of the wave structure 318 can act as an arch, transferringthe radial force provided by the posts along a side surface 616 of thewave structure 318 to the undeformed section 316 of the bearing.Conversely, in the preassembled state, the wave structure 318 is devoidof a continuous parabolic arch, subjecting the wave structure 318 todeflect to the closed, or partially closed, assembled state withouttransferring significant forces to the undeformed section 316. In such amanner, minimal forces can be transferred to the undeformed section 316of the wave structure 318 during insertion of the posts into thebearings.

As illustrated in FIGS. 39A through 39E, in certain embodiments, atleast one wave structure 318 can include an aperture 608 positionedalong at least one of the side surfaces 616. In such a manner, the wavestructure 318 can be at least partially disconnected from the undeformedportion of the sidewall of the bearing. In a non-illustrated embodiment,the wave structures 318 can include an aperture along at least threesides. In such a manner, the wave structure can be disconnected from thesidewall along at least a portion of three sides thereof, e.g., a tine.In an embodiment, the tine can be bent or otherwise deflected in aradial direction. This may increase or decrease radial loading of thewave structure 318 as measured on the post.

The aperture 608 can define any shape when viewed from the side surface616 of the wave structure 318, such as, for example, a generallypolygonal opening, a generally ellipsoidal opening, or a combinationthereof. In particular embodiments, the aperture 608 can be ovular. Inother embodiments, the aperture 608 can be pinched.

FIGS. 39A, 39B, and 39D, show yet a further embodiment of the wavestructure 318 in the initially unassembled state (i.e., prior toinsertion of the posts into the bearings). In this regard, the apertures608 are in the open position. In this position the radial stiffness ofthe wave structure 318 is reduced to allow for easier insertion of theposts into the bearings. In the preassembled state, as shown, (i.e.,prior to post insertion into the bearing) the apertures 608 can extendat least partially along the length of the wave structure 318. Duringinsertion of the post into the bearing, the apertures 608 can at leastpartially close, thereby, enhancing stiffness of the wave structure 318.

FIGS. 39C and 39E show the wave structure 318 in the assembled state(i.e., after insertion of the posts into the bearings). It should beunderstood that in FIGS. 39C and 39E, the apertures 608 are shownexaggerated (i.e., slightly open) in the assembled state and are notdrawn to scale. In practice, the apertures 608 may fully close in theassembled state so as to reveal a continuous side surface 616 devoid ofany opening therein.

In other embodiments, the apertures 608 may substantially close in theassembled state such that small gaps remain along the side surface 616of the wave structure 318.

In the assembled state (e.g., FIGS. 39C and 39E), a radially innermostsurface 614 of the wave structure 318 can act as an arch, transferringthe radial force provided by the posts along a side surface 616 of thewave structure 318 to the undeformed section. Conversely, in thepreassembled state, the wave structure 318 is devoid of a continuousside wall 616, subjecting the wave structure 318 to deflect to theclosed, or partially closed, assembled state without transferringsignificant forces to the undeformed section 316. In such a manner,minimal forces can be transferred to the undeformed section 316 of thewave structure 318 during insertion of the posts into the bearings.

In particular embodiments (e.g., FIGS. 35A, 35B, and 35D), the aperture608 can have at least one tapered end 618 when viewed in a directionperpendicular to the aperture 608. The tapered end 618 can define anacute angle, A_(A), which can be less than about 45 degrees, such asless than about 40 degrees, less than about 35 degrees, less than about30 degrees, less than about 25 degrees, less than about 20 degrees, lessthan about 15 degrees, or even less than about 10 degrees.

In further embodiments, the aperture 608 can have a maximum length,L_(A), and a maximum width, W_(A), as measured perpendicular to L_(A).In particular embodiments a ratio of L_(A):W_(A) can be no less thanabout 1.0, such as no less than about 1.5, no less than about 2.0, noless than about 2.5, no less than about 3.0, no less than about 4.0, noless than about 5.0, no less than about 6.0, no less than about 7.0, noless than about 8.0, no less than about 9.0, no less than about 10.0, noless than about 15.0, no less than about 20.0, no less than about 25.0,or even no less than about 30.0. In further embodiments, the ratio ofL_(A):W_(A) can be no greater than about 500, such as no greater thanabout 400, no greater than about 300, no greater than about 200, nogreater than about 100, no greater than about 75, no greater than about50, or even no greater than about 40. Moreover, the ratio of L_(A):W_(A)can be within a range of between and including any of the valuesdescribed above, such as, for example, about 12.0.

In specific embodiments, a ratio of L_(W):L_(A) can be no greater thanabout 1.25, such as no greater than about 1.0, no greater than about0.95, no greater than about 0.90, no greater than about 0.85, no greaterthan about 0.80, no greater than about 0.75, no greater than about 0.70,no greater than about 0.65, or even no greater than about 0.60. Theratio of L_(W):L_(A) can be no less than about 0.01, such as no lessthan about 0.10, no less than about 0.20, no less than about 0.30, oreven no less than about 0.40. Moreover, the ratio of L_(W):L_(A) can bewithin a range of between and including any of the values describedabove, such as, for example, about 0.90.

In further embodiments, a ratio of W_(W):W_(A) can be no greater thanabout 1.25, such as no greater than about 1.0, no greater than about0.95, no greater than about 0.90, no greater than about 0.85, no greaterthan about 0.80, no greater than about 0.75, no greater than about 0.70,no greater than about 0.65, or even no greater than about 0.60. In yetfurther embodiments, the ratio of W_(W):W_(A) can be no less than about0.01, such as no less than about 0.10, no less than about 0.20, no lessthan about 0.30, or even no less than about 0.40. Moreover, the ratio ofW_(W):W_(A) can be within a range of between and including any of thevalues described above, such as, for example, about 0.4.

Referring now to FIGS. 38A and 38B, in particular embodiments, thesizing feature 606 of the at least one wave structure 318 mayadditionally/alternatively comprise a portion 610 of the wave structure318 having a reduced thickness. In this regard, the undeformed portion316 can have an average thickness, T_(UP), and the wave structure 318can have a portion 610 with a reduced radial thickness, T. A ratio ofT_(P):T_(UP) can be no greater than about 0.99, such as no greater thanabout 0.95, no greater than about 0.90, no greater than about 0.85, nogreater than about 0.80, no greater than about 0.75, no greater thanabout 0.70, no greater than about 0.65, no greater than about 0.60, nogreater than about 0.55, no greater than about 0.50, no greater thanabout 0.40, no greater than about 0.30, or even no greater than about0.20. In further embodiments, the ratio of T_(P):T_(UP) can be no lessthan about 0.05, such as no less than about 0.10, no less than about0.15, or even no less than about 0.20. Moreover, the ratio ofT_(P):T_(UP) can be within a range of between and including any of thevalues described above, such as, for example, about 0.85.

As the ratio of T_(P):T_(UP) decreases, the magnitude of differencebetween the initial unassembled radial stiffness and the assembledradial stiffness can increase while the required assembly force candecrease. As the posts are inserted into the bearings, the wavestructure of FIG. 38A can collapse and the portion 610 of the wavestructure 318 having a reduced thickness can become thicker.

In this regard, the portion 610 of the wave structure 318 having areduced thickness can have an initial unassembled radial stiffness, S₁(as shown in FIG. 38A), and an assembled radial stiffness, S₂ (as shownin FIG. 38B), wherein S₂ is greater than S₁. In particular embodiments,a ratio of S₂:S₁ can be no less than about 1.01, such as no less thanabout 1.05, no less than about 1.10, no less than about 1.20, no lessthan about 1.30, no less than about 1.40, no less than about 1.50, noless than about 1.75, or even no less than about 2.00. In furtherembodiments, the ratio of S₂:S₁ can be no greater than about 20, such asno greater than about 15, no greater than about 10, no greater thanabout 5, or even no greater than about 3. Moreover, the ratio of S₂:S₁can be within a range of between and including any of the abovedescribed values, such as, for example, between about 2.1 and about 2.5.

In particular embodiments, the portion 610 having the reduced thicknesscan have a surface area, A_(P), as measured along an outer surface ofthe wave structure 318 and the wave structure 318 can have a totalsurface area, A_(W). In particular embodiments, a ratio of A_(P):A_(W)can be no less than about 0.05, such as no less than about 0.10, no lessthan about 0.15, no less than about 0.20, no less than about 0.25, noless than about 0.30, no less than about 0.35, no less than about 0.40,no less than about 0.45, no less than about 0.50, no less than about0.60, no less than about 0.70, no less than about 0.80, or even no lessthan about 0.90. In further embodiments, the ratio of A_(P):A_(W) can beno greater than about 0.99, such as no greater than about 0.98, nogreater than about 0.97, no greater than about 0.96, no greater thanabout 0.95, no greater than about 0.94, no greater than about 0.93, nogreater than about 0.92, no greater than about 0.91, or even no greaterthan about 0.90. Moreover, the ratio of A_(P):A_(W) can be within arange of between and including any of the values described above, suchas, for example, about 0.45.

Referring to FIGS. 40A and 40B, in yet other embodiments, the sizingfeature 606 of the at least one wave structure 318 mayadditionally/alternatively comprise a dimpled section 612. The dimpledsection 612 can include corrugations, bumps, indents, or any similarstructure which is adapted to deform (collapse) during insertion of theposts into the bearings. In a particular aspect, the dimpled section 612can be adapted to have a greater radial stiffness after the post isinserted into the bearing as compared to the radial stiffness prior toinsertion.

In particular embodiments, the dimpled section 612 can comprise acorrugation 620. Moreover, in more particular embodiments, thecorrugation 620 can further comprise a plurality of corrugations. Incertain embodiments, the corrugation(s) 620 can be positioned along theinner surface 614 of the wave structure 318 or partially there along.

In further embodiments, the dimpled section 612 can comprise aperforation 622. In more particular embodiments, the perforation 622 canfurther comprise a plurality of perforations. The perforation(s) 622 cancause the wave structure 318 to have an overall initial unassembledradial stiffness, S₁, and an assembled radial stiffness, S₂. Inparticular embodiments, a ratio of S₂:S₁ can be no less than about 1.01,such as no less than about 1.05, no less than about 1.10, no less thanabout 1.20, no less than about 1.30, no less than about 1.40, no lessthan about 1.50, no less than about 1.75, or even no less than about2.00. In further embodiments, the ratio of S₂:S₁ can be no greater thanabout 20, such as no greater than about 15, no greater than about 10, nogreater than about 5, or even no greater than about 3. Moreover, theratio of S₂:S₁ can be within a range of between and including any of theabove described values, such as, for example, between about 2.1 andabout 2.5.

Referring again to FIG. 1 through FIG. 3B, the guide sleeves 200, 202can include a locking mechanism 400. The locking mechanism 400 can beengaged with the seat back 4 so as to prevent the posts 100, 102 fromtranslating undesirably relative thereto. The locking mechanism 400 canbe formed with an internal bore 402 adapted to receive one of the posts100, 102. In a particular embodiment, the assembly 1 can additionallycomprise a component 456 having substantially the same shape andfeatures as the locking mechanism 400, including an internal bore 402adapted to receive the second post 102.

In a particular embodiment, the assembly 1 can include guide sleeves200, 202 adapted to be engaged with one of the first and second posts100, 102. As illustrated in FIG. 17, the first guide sleeve 200 caninclude a locking mechanism 400 and bearing 300. The other of the guidesleeves 200, 202 can include the bearing 302 and the component 456.

In another embodiment, each guide sleeve 200, 202 can include twosubstantially identical locking mechanisms 400—the first lockingmechanism 400 engaged with the first bearing 300, and a second lockingmechanism 400 engaged with the second bearing 302.

Referring to FIG. 17 through FIG. 20, the locking mechanism 400 includesa housing 404 having a bore defining an axial cavity 418 there through.The axial cavity 418 can have a central axis 420 extending from a bottomend 422 of the locking mechanism 400 to a top end 424 of the lockingmechanism 400.

In a particular embodiment, the housing 404 can be cylindrical, having aheight, H_(H), and a main diameter, D_(H). The central axis 420 canextend parallel with an outer surface 426 of the housing 404. The axialcavity 418 can have a diameter, D_(C), wherein a ratio of D_(H):D_(C)can be at least 1.1, such as at least 1.2, at least 1.3, at least 1.4,at least 1.5, at least 1.6, at least 1.7, at least 1.8, at least 1.9, atleast 2.0, at least 2.5, or even at least 3. The ratio of D_(H):D_(C)can be no greater than 5.0, such as no greater than 4.5, no greater than4.0, no greater than 3.5, no greater than 3.0, no greater than 2.5, oreven no greater than 2.0. The ratio of D_(H):D_(C) can also be within arange between and including any of the ratio values described above,such as between 1.1 and 5.0.

A ratio of D_(C):D_(P) can be no greater than 2.0, such as no greaterthan 1.5, no greater than 1.25, no greater than 1.2, no greater than1.1, no greater than 1.05, or even no greater than 1.025. The ratio ofD_(C):D_(P) can be no less than 1.001, such as no less than 1.005, noless than 1.01, no less than 1.025, no less than 1.05, or even no lessthan 1.75. Additionally, the ratio of D_(C):D_(P) can also be within arange between and including any of the ratio values described above. Asthe ratio of D_(C):D_(P) decreases beyond a particular point, thefrictional resistance between the posts 100, 102 and the housing 404 ofthe locking mechanism 400 can increase. The increasing frictionalresistance can impact the ease by which an occupant of the vehicle canadjust the head restraint assembly 1.

In a further embodiment, the housing 404 can be formed with a firstcylindrical section 428 and a second cylindrical section 430 engagedthere below. The first cylindrical section 428 can have an outerdiameter, OD_(H1), and the second cylindrical section 430 can have anouter diameter, OD_(H2). A ratio of OD_(H1):OD_(H2) can be no less than0.5, such as no less than 0.75, no less than 1.0, no less than 1.25, noless than 1.5, or even no less than 2.0. The ratio of OD_(H1):OD_(H2)can be no greater than 5.0, such as no greater than 4.5, no greater than4.0, no greater than 3.5, no greater than 3.0, no greater than 2.5, nogreater than 2.0, or even no greater than 1.5. Additionally, the ratioof OD_(H1):OD_(H2) can also be within a range between and including anyof the ratio values described above. In a further embodiment,OD_(H1):OD_(H2) can be approximately 2. In this regard, the secondcylindrical section 430 can have an outer diameter that is approximatelyone-half the outer diameter of the first cylindrical section 428.

The first cylindrical section 428 can have a height, H_(H1), and thesecond cylindrical section 430 can have a height, H_(H2), wherein aratio of H_(H1):H_(H2) can be no less than 0.25, such as no less than0.5, no less than 0.75, no less than 1.0, no less than 1.5, or even noless than 2.0. The ratio of H_(H1):H_(H2) can be no greater than 5.0,such as no greater than 4.5, no greater than 4.0, no greater than 3.5,no greater than 3.0, no greater than 2.5, no greater than 2.0, or evenno greater than 1.5. Additionally, the ratio of H_(H1):H_(H2) can alsobe within a range between and including any of the ratio valuesdescribed above.

The housing 404 can comprise any suitable material with sufficientrigidity to withstand axial and longitudinal forces. In a particularembodiment, the housing 404 can comprise an injection molded polymer. Inanother embodiment, the housing 404 can comprise a metal or alloy formedthrough a machining process. In yet another embodiment, the housing 404can comprise a ceramic or any other suitable material. The housing 404can be formed from a single piece, two pieces, or several pieces joinedtogether by welding, adhesive, fasteners, threading, or any othersuitable fastening means.

In a particular aspect, the housing 404 can be mated such that thebottom of the first cylindrical section is flush with the top surface 6of the seat back 4. In this regard, the housing 404 can be partiallyvisible to occupants within the vehicle. In a further aspect, thehousing 404 can be mounted above the top surface 6 of the seat back 4.

In a particular aspect, as illustrated in FIG. 21, the bearings 300, 302can be adapted to fit within the axial cavity 418 of the housing 404. Inthis regard, the axial cavity 418 can have an inner diameter, ID_(AC),and the bearings 300, 302 can have an outer diameter, OD_(B). A ratio ofID_(AC):OD_(B) can be no greater than 1.20, such as no greater than1.15, no greater than 1.10, no greater than 1.09, no greater than 1.08,no greater than 1.07, no greater than 1.06, no greater than 1.05, nogreater than 1.04, no greater than 1.03, no greater than 1.02, or evenno greater than 1.01. The ratio of ID_(AC):OD_(B) can be greater than 1,such as greater than 1.01, greater than 1.02, greater than 1.03, greaterthan 1.04, greater than 1.05, or even greater than 1.10. Additionally,the ratio of ID_(AC):OD_(B) can also be within a range between andincluding any of the ratio values described above.

To engage one of the bearings 300, 302 with the locking mechanism 400and the other bearing 300, 302 with the component 456, the first ends306 of the bearings 300, 302 can be inserted into the cavity 418 of thehousing 404. The bearings 300, 302 can be aligned with the lockingmechanism 400 and component 456 such that the central axis 420 of thecavity 418 aligns with the central axis 322 of the bearings 300, 302. Ina particular aspect, the bearings 300, 302 can further include anengagement structure 326 to secure with the housing 404. The guidecenter axis 306 can be parallel and concomitant with the first centeraxis 420 of the cavity 418.

In a particular embodiment, illustrated in FIG. 22, the engagementstructure can comprise at least one L-shaped cutout 326 in each of thebearings 300, 302. Each of the L-shaped cutouts 326 can have an opening328 extending axially inward from the first end 306 of the bearing 300,302; a heel 330 at the base of the opening 328; a sliding lock surface332 extending from the heel 330; and an end 334 at a terminal side ofthe sliding lock surface 332. An inner surface of the housing 404 canfurther include at least one tab 408 extending radially inward into thecavity 418, substantially perpendicular to the center axis 420. Toinstall the bearings 300, 302 into the housings 404, each of thebearings 300, 302 can be aligned such that the tab 408 fits within theopening 328 of the bearings 300, 302. The bearings 300, 302 can be urgedinto the cavity 418 until the heel 330 of each L-shaped cutout 326 makescontact with each tab 408. After the tabs 408 come into contact with theheel 330, the bearings 300, 302 can be rotated such that the tabs 408translates on the sliding lock surface 332 until the tabs 408 contactthe end 334 of the L-shaped cutout 326.

The bearings 300, 302 can be secured to the housing 404 in any methodrecognizable to one having ordinary skill in the art. For example, in analternative embodiment, the bearings 300, 302 can threadably engage tothe housing 404. Each of the bearings 300, 302 can include a firstthread and the housing 404 can include a complementary second thread. Inanother embodiment, the bearings 300, 302 can be secured to the housing404 by an adhesive. In yet a further embodiment, the bearings 300, 302can be secured to the housing 404 by an interference fit. In a furtherembodiment, the bearings 300, 302 can be secured to the housing 404 by apin or a fastener. In yet a further embodiment, the bearings 300, 302can be secured to the housing 404 by a bayonet connection.

Referring again to FIG. 17 to FIG. 20, the locking mechanism 400 canfurther include a locking member 432 positioned within the housing 404.

As illustrated in FIG. 23 through FIG. 25, the locking member 432 cancomprise an opening 434 having a central axis 436, and a first andsecond surface 438 and 440. Moreover, the locking member 432 canadditionally include at least one biasing element 442 extending from thesecond surface 440 of the locking member 432. The biasing element 442can be adapted to provide a biasing force relatively parallel with thecentral axis 436. The biasing element 442 can be a spring. In aparticular embodiment, the biasing element 442 can be a leaf springextending from the second surface 440 of the locking member 432. In aparticular aspect, the leaf spring 442 can be formed integrally from thelocking member 432. The leaf spring 442 can be formed from a cutout fromthe locking member 432. The surface can be rotated away from the secondsurface 440 of the locking member 432. The surface can comprise at leastone bend therein to facilitate enhanced engagement between the leafspring 442 and the housing 404.

Moreover, the locking member 432 can further include a distal flange 446projecting from the locking member 432 at an angle, A_(F). In aparticular aspect, A_(F) can be no less than 45 degrees, such as no lessthan 50 degrees, no less than 55 degrees, no less than 60 degrees, noless than 65 degrees, no less than 70 degrees, no less than 75 degrees,no less than 80 degrees, no less than 85 degrees, no less than 90degrees, no less than 95 degrees, no less than 100 degrees, no less than105 degrees, or even no less than 110 degrees. A_(F) can be no greaterthan 170 degrees, such as no greater than 165 degrees, no greater than160 degrees, no greater than 155 degrees, no greater than 150 degrees,no greater than 145 degrees, no greater than 140 degrees, no greaterthan 135 degrees, no greater than 130 degrees, no greater than 125degrees, no greater than 120 degrees, no greater than 115 degrees, nogreater than 110 degrees, no greater than 105 degrees, no greater than100 degrees, no greater than 95 degrees, or even no greater than 90degrees. Additionally, A_(F) can also be within a range between andincluding any of the values described above.

In a further embodiment, the locking member 432 can also include a lever448 extending from the first surface 438 of the locking member 432opposite the flange 446. In a particular aspect, the lever 448 can beformed by rolling an edge of the locking member 432 over on itself. Inthis regard, the lever 448 can be integrally formed from the lockingmember 432, increasing strength of the lever 448 while simultaneouslyreducing the need for a weld or joint. In an alternate embodiment, thelever 448 can be formed from a material that is attached to the lockingmember by welding or adhesive. In yet another embodiment, the lever 448can be formed similar to the flange 446. The lever 448 can be formedfrom the surface of the locking member 432 that is bent at asubstantially right-angle. In operation, the lever 448 is adapted tocant the locking member 432 at an angle, A_(C), when positioned therebelow. As will become apparent to one having ordinary skill in the art,the locking member 432, having the relative canting angle, A_(C), can beadapted to facilitate an interference fit with at least one of the posts100, 102. As the locking member 432 is canted relative to the post 100,102 being engaged, the locking member 432 can prevent axial translationof the post 100 or 102 within the opening 434.

In a particular embodiment, A_(C) can be no less than 1 degree, such asno less than 2 degrees, no less than 3 degrees, no less than 4 degrees,no less than 5 degrees, no less than 10 degrees, no less than 15degrees, no less than 20 degrees, no less than 25 degrees, no less than30 degrees, no less than 35 degrees, or even no less than 40 degrees.A_(C) can be no greater than 60 degrees, no greater than 55 degrees, nogreater than 50 degrees, no greater than 45 degrees, no greater than 40degrees, no greater than 35 degrees, no greater than 30 degrees, nogreater than 25 degrees, no greater than 20 degrees, no greater than 15degrees, or even no greater than 10 degrees. A_(C) can also be within arange between and including any of the values described above. WhileA_(C) can be selected to be within the above described range, the valueselected is directly dependent on the diameter of the opening 434 andthe diameter of the posts 100, 102.

When the locking member 432 is seated on a level surface such that thelever 448 forms a point of contact between the locking member 432 andthe surface there below, the locking member 432 can have a maximumheight, H_(LM), as defined by the distance between the surface and thetop point 458 furthest therefrom.

The opening 434 of the locking member 432 can have a diameter, D_(O),wherein D_(O) is greater than D_(C). In a particular aspect, a ratio ofD_(O):D_(C) is at least 1.05, such as at least 1.1, at least 1.15, atleast 1.2, at least 1.25, at least 1.3, at least 1.35, at least 1.4, atleast 1.45, or even at least 1.5. The ratio of D_(O):D_(C) is no greaterthan 2.0, such as no greater than 1.9, no greater than 1.8, no greaterthan 1.7, no greater than 1.6, no greater than 1.5, no greater than 1.4,no greater than 1.3, no greater than 1.2, or even no greater than 1.1.Additionally, the ratio of D_(O):D_(C) can also be within a rangebetween and including any of the values described above. The ratio ofD_(O):D_(C) will be obvious to one having ordinary skill in the art inlight of this disclosure.

As illustrated in FIG. 26, FIG. 27A, and FIG. 27B, the locking member432 can be positioned within a slot 409 in the housing 404. In aparticular embodiment, the slot 409 can be oriented substantiallyperpendicular to the central axis 420 of the cavity 418. The slot 409can have a top wall 412 and a bottom wall 414 and can include three sidewalls 416. The slot 409 can form a substantially rectangular cuboidhaving a height, H_(S), a length L_(S), and a width, W_(S).

In a particular embodiment, the slot 409 can include a top wall 410, abottom wall 412 and can include at least two side walls 416. In thisembodiment, the locking member 432 is visible through the housing 404from the two sides of the cuboidal slot 409 not including side walls416.

In a particular aspect, a ratio of H_(S):H_(LM) can be at least 0.9,such as at least 0.95, at least 1.0, at least 1.01, at least 1.02, atleast 1.03, at least 1.04, at least 1.05, at least 1.06, at least 1.07,at least 1.08, at least 1.09, at least 1.10, at least 1.15, or even atleast 1.2. The ratio of H_(S):H_(LM) can be no greater than 1.4, such asno greater than 1.35, no greater than 1.3, no greater than 1.25, nogreater than 1.2, no greater than 1.15, no greater than 1.1, no greaterthan 1.05, no greater than 1.04, no greater than 1.03, no greater than1.02, no greater than 1.01, or even no greater than 1.0. The ratio ofH_(S):H_(LM) can also be within a range between and including any of thevalues described above. In the event the ratio of H_(S):H_(LM) has avalue of less than 1.0, the locking member 432 can be compressed withinthe slot 409 by the top wall 412 of the slot 409, such that the toppoint 458 is urged towards the lever 448. The application of force onthe top point 458 towards the lever 448 may enhance the grippingproperties of the locking member 432 with the posts 100, 102. Inparticular, as the force applied against the top point 458 increases,the relative gripping power exhibited by the locking member 432 againstthe post 100 or 102 disposed of therein can increase.

As illustrated in FIG. 28, the locking member 432 can be angularlypositioned relative to the central axis 420, resulting in a relativeacute angle formed between the central axis 420 and the central axis436. This acute angle, as illustrated in FIG. 29, can be equal to thecanting angle, A_(C), of the locking member 432. In a particularembodiment, as the locking member 432 is canted at a higher angle,A_(C1), the angle between the central axes 420 and 436 increases anequal value. As the angle, A_(C1), increases, the locking member 432 canbe adapted to form an interference fit with the posts 100, 102. Thisinterference fit can prevent the posts 100, 102 from translating alongthe central axis 436 of the cavity 418 in either vertical direction(i.e., upward or downward).

As illustrated in FIG. 30, the locking member 432 can be adapted suchthat the central axis 420 of the cavity 418 substantially aligns withthe central axis 436 of the opening 434. At this position, the lockingmember 432 is canted at a lesser angle, A_(C2). In this position, thelocking member 432 can be adapted to permit the posts 100, 102 totranslate within the cavity 418 in either vertical direction (i.e.,upward or downward). Angle A_(C2) is shown in FIG. 31.

As shown in FIG. 32 and FIG. 33, the locking mechanism 400 can furthercomprise an actuating member 450 engaged at least partially in the slot409 between the housing 404 and the flange 446 of the locking member432.

In a particular embodiment, the actuating member 450 can be adapted totranslate in a direction substantially perpendicular to the central axis420. As the actuating member 450 translates radially inward towards thecentral axis 420 the actuating member 450 can engage the flange 446 ofthe locking mechanism 400, angularly rotating the locking member 432around the lever 448 and displacing the flange 446 in a directionparallel with the central axis 420. As the locking member 432 rotatesaround the lever 448 the angle, A_(C), decreases, causing the first andsecond axes 420 and 436 to become more closely aligned.

In a particular aspect, the actuating member 450 can comprise a plungerhaving an angled plunger face 454 adapted to engage with the flange 446of the locking member 432. The plunger face 454 can have a plungerangle, A. In a particular aspect, A_(P) can be greater than 30 degrees,such as greater than 35 degrees, greater than 40 degrees, greater than45 degrees, greater than 50 degrees, greater than 55 degrees, greaterthan 60 degrees, greater than 65 degrees, greater than 70 degrees,greater than 75 degrees, greater than 80 degrees, greater than 85degrees, greater than 90 degrees, greater than 95 degrees, or evengreater than 100 degrees. A_(P) can be less than 150 degrees, such asless than 145 degrees, less than 140 degrees, less than 135 degrees,less than 130 degrees, less than 125 degrees, less than 120 degrees,less than 115 degrees, less than 110 degrees, less than 105 degrees,less than 100 degrees, less than 95 degrees, or even less than 90degrees. Furthermore, the A_(P) can be in a range between and includingany of the values described above.

In a particular embodiment, the plunger face 454 can mate with theflange 446 such that upon translating towards the central axis 420, theplunger face 454 displaces the flange upward. This in turn, can beunderstood to decrease A_(C) and align the central axis 436 of theopening 434 of the locking member 432 with the central axis 420 of thecavity 418 of the housing 404.

Referring again to FIG. 24 through FIG. 31, it can be understood thatthe locking member 432 is in a first position when angle A_(C1) isgreatest. Conversely, it can be understood that the locking member 432is in a second position when angle A_(C2) is smallest.

In operation, one of the posts 100, 102 can be adapted to fitsimultaneously within the cavity 418 of the housing 404 and the opening434 of the locking member 432. When in the first position, the lockingmember 432 can prevent the posts 100, 102 from translating in a firstdirection, as represented in FIG. 1 by line 500. The locking mechanism400 can prohibit the translation of the posts 100, 102 in the firstdirection (represented by line 500) upon the application of five secondsof applied force in the first direction of 500 Newtons (N).

The posts 100, 102 can be prohibited from translating in the firstdirection by an interference formed between the cavity 418 and theopening 434 of the locking member 432. More specifically, theinterference can be formed between the central axes 420 and 436. As thecentral axis 420 of the cavity 418 cants relative to the central axis436 of the opening 434, a biting edge 458 of the of the locking member432 can engage the post 100, 102. It can be understood that the bitingedge 458 can prevent axial translation of the posts 100, 102 through theopening 434 in the direction in which the locking member 432 isoriented. In a particular embodiment, the posts 100, 102 can beprohibited from translating axially in a direction towards the bitingedge 106 upon application of a force of less than 500 N, as sustainedfor five seconds.

In a particular aspect, the biting edge 458 can comprise teeth extendingradially inward. In another aspect, the biting edge 458 can comprise aroughened surface. In yet a further aspect, the biting edge 458 can behave a sharp lip capable of forming a groove or channel in the outersurface of the posts 100, 102. In another aspect, the biting edge 458can comprise a rolled over surface 460 of the locking member 432.

While the locking member 432 is in oriented in the first position, theposts 100, 102 can translate in a second direction, as represented inFIG. 1 by line 502, upon an application of force of no greater than 45N, such as no greater than 40 N, no greater than 35 N, no greater than30 N, no greater than 25 N, no greater than 20 N, no greater than 15 N,no greater than 10 N, or even no greater than 5 N.

The locking member 432 can be adapted to prevent relative axialtranslation of the posts 100, 102 within the cavity 418 of the housing404 in a first direction (represented by line 500) upon the applicationof force in the first direction of no greater than 500 N, whilesimultaneously permitting translation of the posts 100, 102 within thecavity 418 of the housing 404 upon the application of a force in thesecond direction (represented by line 502) of no greater than 45 N.

In a particular aspect, the posts 100, 102 can translate axially withinthe cavity 418 upon the application of no greater than 45 N in both thefirst or second directions when the locking member 432 is oriented inthe second position. In the second position, the interference fitbetween the axes 420 and 436 is reduced, allowing for substantially freeaxial translation of the posts 100, 102 within the cavity 418 along thecentral axis 436.

In a particular aspect, it is possible to minimize variance between headrestraint assemblies 1 in accordance with embodiments herein. Previousadjustable head restraint assemblies have been manufactured such thatthe head restraint posts are intentionally misaligned and not orientedparallel with one another. This misalignment allows the posts to form aninterference fit with the seat back. This misalignment has severalunintended consequences. Particularly, these previous assemblies canexhibit a high standard deviation in tolerance and slidability. As aresult, the forces to slide the assembly vertically in the upward anddownward directions can vary substantially between assemblies.Additionally, previous adjustable head restraint assemblies can rattleand even squeak during vehicular operation as the post can move radiallyrelative to the seat back, rattling against the seat back.

Embodiments can minimize the standard deviation between commercial lotsof assemblies. Specifically, because various embodiments do not rely onpost misalignment to form an interference fit between the posts and theseat back, the force required to translate each of a lot of headrestassemblies vertically in the upward and downward directions can have astandard deviation of no greater than 5 Newtons (N), such as no greaterthan 4 N, no greater than 3 N, no greater than 2, or even no greaterthan 1 N. As a result, the variance between assemblies can be reduced.

Moreover, reaction to radial deflection can be such that deflection ofthe internal framework 10 of the cushion 8 upon the application of 20 Nof force perpendicular to the central axis 420 can be no greater than 5mm. The deflection of the framework 10 of the headrest cushion 8 canvary by no greater than 4 mm, no greater than 3 mm, or even no greaterthan 2 mm. Accordingly, the standard deviation of deflection can be nogreater than 1.8 mm, such as no greater than 1.6 mm, no greater than 1.5mm, no greater than 1.4 mm, no greater than 1.3 mm, no greater than 1.2mm, no greater than 1.1 mm, no greater than 1 mm, no greater than 0.9mm, no greater than 0.8 mm, no greater than 0.7 mm, no greater than 0.6mm, no greater than 0.5 mm, no greater than 0.4 mm, no greater than 0.3mm, no greater than 0.2 mm, or even no greater than 0.1 mm.Additionally, the standard deviation can be within a range between andincluding any of the ratio values described above.

In a particular aspect, the commercial lot being test for variance caninclude at least 30 assemblies, such as at least 50 assemblies, at least100 assemblies, at least 200 assemblies, at least 500 assemblies, ateven at least 1,000 assemblies.

Many different aspects and embodiments are possible. Some of thoseaspects and embodiments are described below. After reading thisspecification, skilled artisans will appreciate that those aspects andembodiments are only illustrative and do not limit the scope of thepresent invention. Embodiments may be in accordance with any one or moreof the items as listed below.

Category 1

Item 1. A guide sleeve, comprising: a bearing comprising a generallycylindrical body having a sidewall, wherein the sidewall includes anundeformed portion, a plurality of wave structures protruding radiallyinward from the undeformed portion; and a locking mechanism coupled tothe bearing, wherein the locking mechanism is adapted to engage a post.

Item 2. An adjustable head restraint assembly, comprising: a headrestraint comprising a member and a first and second post extending fromthe member; a frame for receiving the head restraint, the frameincluding a first and second mounting fixture for the first and secondposts; a first guide sleeve according to claim 1, the first guide sleeveaffixed to the first mounting fixture and slidably engaged to the firstpost; and a second guide sleeve, the second guide sleeve affixed to thesecond mounting fixture and slidably engaged to the second post.

Item 3. The guide sleeve according to any one of the preceding items,wherein the body has an axial length, and wherein the body furthercomprises a gap extending along the entire axial length of the body,wherein the gap establishes a split in the body.

Item 4. The guide sleeve according to item 4, wherein the gapestablishes a split in the body defining a first end and a second end.

Item 5. The guide sleeve according to any one of the preceding items,wherein at least three wave structures extend circumferentially aroundthe body as seen in a cross-section perpendicular to the central axis ofthe bearing.

Item 6. The guide sleeve according to any one of the preceding items,wherein each wave structure has a length, L_(WS), wherein the bearinghas an axial length, L_(B), and wherein L_(WS) is at least 0.3 L_(B).

Item 7. The guide sleeve according to item 6, wherein there are at leasttwo rows of wave structures, wherein the rows of wave structures areseparated by at least 0.1 L_(B).

Item 8. The guide sleeve according to any one of the preceding items,wherein the wave structures are axially staggered on the sidewall.

Item 9. The guide sleeve according to any one of the preceding items,wherein the bearing comprises a composite structure.

Item 10. The guide sleeve according to any one of the preceding items,wherein the bearing comprises a backing and a low friction layer.

Item 11. The guide sleeve according to item 10, wherein the backing is ametal substrate.

Item 12. The guide sleeve according to any one of items 10-11, whereinthe low friction layer comprises a polymer.

Item 13. The guide sleeve according to any one of items 10-12, whereinthe low friction layer comprises a fluoropolymer.

Item 14. The guide sleeve according to any one of items 10-13, whereinthe low friction layer comprises PTFE.

Item 15. The guide sleeve according to any one of items 10-14, whereinthe low friction layer is positioned radially inside of the backing.

Item 16. The guide sleeve according to any one of the preceding items,wherein the locking mechanism further comprises at least one tabextending radially inward, wherein the bearing comprises a groove, andwherein the tab of the locking mechanism is adapted to engage with thegroove of the bearing.

Item 17. The guide sleeve according to item 16, wherein the groovecomprises an L-shape.

Item 18. The assembly according to any one of items 2-17, wherein eachof the guide sleeves is welded, adhered, or mechanically interlocked toeach of the mounting fixtures.

Item 19. The assembly according to any one of the preceding items,wherein the first and second posts are substantially parallel to eachother.

Category 2

Item 1. A commercial lot of head restraint assemblies, including atleast 20 assemblies, each assembly comprising: a head restraintcomprising a body and a first and a second post extending from the body;a frame for receiving the head restraint, the frame including a firstand s second mounting fixture for the first and second posts,respectively; a first bearing fitted between the first post and thefirst mounting fixture; and a second bearing fitted between the secondpost and the second mounting fixture, wherein a force required totranslate each of the head restraints in the vertically upward directionis not greater than 45 Newtons (N), and the force varies in thecommercial lot by a standard deviation of no greater than 5 N.

Item 2. The commercial lot of head restraint assemblies according to thepreceding item, wherein each of the head restraints deflects no greaterthan 2.5 mm upon an application of force of 20 N perpendicular to theplanar axis.

Item 3. The commercial lot of head restraint assemblies according to anyone of the preceding items, wherein the standard deviation is no greaterthan 4.5 N, no greater than 4 N, no greater than 3.5 N, no greater than3 N, no greater than 2.5 N, no greater than 2 N, no greater than 1.5 N,or even no greater than 1 N.

Item 4. The commercial lot of head restraint assemblies according to anyone of the preceding items, wherein the commercial lot includes at least30 assemblies, such as at least 50 assemblies, at least 100 assemblies,at least 200 assemblies, at least 500 assemblies, or even at least 1,000assemblies.

Item 5. The commercial lot of head restraint assemblies according to anyone of the preceding items, wherein the first and second bearingscomprise metal.

Item 6. The commercial lot of head restraint assemblies according to anyone of the preceding items, wherein the first and second bearingsfurther comprise a low friction layer engaged with the bearing, andwherein the low friction layer forms an inner surface of the bearing.

Item 7. The commercial lot of head restraint assemblies according toitem 6, wherein the low friction layer comprises a polymer.

Item 8. The commercial lot of head restraint assemblies according to anyone of items 7-7, wherein the low friction layer comprises afluoropolymer, such as PTFE.

Item 9. The commercial lot of head restraint assemblies according to anyone of the preceding items, further comprising a locking member, thelocking member coupled to one of the first and second bearings, whereinthe locking member is adapted to prevent axial translation of the postsrelative to the first and second bearings in at least one axialdirection.

Item 10. The commercial lot of head restraint assemblies according toany one of the preceding items, further comprising a locking memberhaving an opening including a central axis, wherein the locking memberis adapted to receive the post, the post having a central axis, thelocking member being adapted to be movable between a first position anda second position, wherein in the first position the central axis of thelocking member and the central axis of the post are non-parallel andintersect at an acute angle, A_(I), and wherein in the second positionA_(I) is lesser than A_(I) in the first position.

Item 11. The commercial lot of head restraint assemblies according toany one of the preceding items, wherein the bearings further comprise aplurality of wave structures.

Item 12. The commercial lot of head restraint assemblies according toitem 11, wherein the wave structures project radially inward.

Item 13. The commercial lot of head restraint assemblies according toany one of the preceding items, wherein the first bearing forms azero-clearance fit with the first post, and wherein the second bearingforms a zero-clearance fit with the second post.

Category 3

Item 1. A head restraint height adjustment apparatus, comprising: ahousing including a bore defining an axial cavity having a central axis;a locking member positioned within the housing, wherein the lockingmember is biased to cant relative to the central axis of the cavity.

Item 2. A head restraint height adjustment apparatus, comprising: ahousing comprising a bore defining an axial cavity having a centralaxis; and a locking member positioned within the housing, the lockingmember having an opening including a central axis, the opening being inopen communication with the bore, the locking member being adapted to bemovable between a first position and a second position, wherein in thefirst position the central axes are non-parallel and intersect at anacute angle, A_(I1), wherein in the second position the central axesintersect at an angle, A_(I2), and wherein A_(I2) is less than A_(I1).

Item 3. A head restraint height adjustment apparatus, comprising: ahousing comprising a bore defining an axial cavity having a centralaxis; a locking member positioned within the housing, the locking memberhaving an opening including a central axis, the opening being in opencommunication with the bore, the locking member being adapted to bemovable between a first position and a second position, wherein in thefirst position the central axes are non-parallel and intersect at anacute angle, A_(I1), wherein in the second position the central axesintersect at an angle, A_(I2), and wherein A_(I2) is less than A_(I1);and wherein the locking member is adapted to receive a post, and whereinthe locking member is adapted to prevent the post from translating in avertically downward direction upon application of a force of 500 Newtonssustained for 5 seconds when the locking member is in the firstposition.

Item 4. The apparatus according to any one of items 2 or 3, furthercomprising an actuation member adapted to move the locking memberbetween the first and second positions.

Item 5. The apparatus according to any one of the items 3-4, wherein atleast one of the first and second posts are devoid of external notches.

Item 6. The apparatus according to any one of items 3-5, wherein eachpost has an adjustment length, as defined by a length of the post thatis visible when the apparatus is at a maximum height, and wherein thelocking member is adapted to engage the post at any position along theadjustment length.

Item 7. The apparatus according to any one of items 2-6, wherein A_(I1)is at least 1 degree, such as at least 2 degrees, at least 3 degrees, atleast 4 degrees, at least 5 degrees, at least 10 degrees, at least 15degrees, at least 20 degrees, at least 25 degrees, at least 30 degrees,at least 35 degrees, at least 40 degrees, or even at least 45 degrees.

Item 8. The apparatus according to any one of items 2-7, wherein A_(I2)is at least 1 degree less than A_(I2), such as at least 2 degrees less,at least 3 degrees less, at least 4 degrees less, at least 5 degreesless, at least 6 degrees less, at least 7 degrees less, at least 8degrees less, at least 9 degrees less, at least 10 degrees less, atleast 15 degrees less, or even at least 20 degrees less.

Item 9. The apparatus according to any one of items 2-8, wherein A_(I2)is less than 10 degrees, such as less than 5 degrees, less than 4degrees, less than 3 degrees, less than 2 degrees, or even less than 1degree.

Item 10. The apparatus according to any one of items 2-9, wherein A_(I2)is approximately 0 degrees.

Item 11. The apparatus according to any one of the preceding itemswherein the bore has an inner diameter, ID_(B), wherein the bore isadapted to receive a post having an outer diameter, OD_(E), and whereinID_(B) is greater than OD_(E).

Item 12. The apparatus according to item 11, wherein a ratio ofID_(B):OD_(P) is at least 1.01, such as at least 1.1, at least 1.15, atleast 1.2, at least 1.25, or even at least 1.3.

Item 13. The apparatus according to any one of items 11-12, wherein aratio of ID_(B):OD_(P) is no greater than 1.5, such as no greater than1.4, no greater than 1.3, no greater than 1.2, or even no greater than1.1.

Item 14. The apparatus according to any one of items 2-13, wherein thearea of the opening of the locking ring as viewed along the central axisof the cavity is greater when the locking member is in the secondposition than when the locking member is in the first position.

Item 15. The apparatus according to any one of items 2-14, wherein asviewed along the central axis of the cavity, the opening of the lockingmember has a first perceptible area, A_(LM1), wherein as viewed alongthe central axis of the cavity the opening of the locking member has asecond perceptible area, A_(LM2), and wherein A_(LM1) is less thanA_(LM2).

Item 16. The apparatus according to item 15, wherein a ratio ofA_(LM1):A_(LM2) is less than 0.99, such as less than 0.95, less than0.90, less than 0.85, less than 0.80, less than 0.75, less than 0.70,less than 0.65, or even less than 0.60.

Item 17. The apparatus according to any one of items 15-16 wherein aratio of A_(LM1):A_(LM2) is greater than 0.45, such as greater than0.50, greater than 0.55, greater than 0.60, greater than 0.65, greaterthan 0.70, greater than 0.75, or even greater than 0.80.

Item 18. The apparatus according to any one of items 2-17, wherein thelocking member is biased to the first position by a biasing element.

Item 19. The apparatus according to item 18, wherein the biasing elementis a leaf spring.

Item 20. A head restraint height adjustment apparatus, comprising: ahead restraint comprising a body and a first and second post extendingfrom the body, at least the first post being devoid of external notches;and a locking member adapted to engage the first post along anadjustment length, wherein in a locked position the locking memberprevents downward axial translation of the first post, and wherein in anunlocked position the locking member permits both upward and downwardaxial translation of the first post.

Item 21. The head restraint height adjustment apparatus according toitem 20, wherein the locking member is adapted to engage the first postsuch that in the unlocked position the post can translate freely upwardand downward by application of a force not greater than 45 Newtons, andin the locked position the post is prevented from downward translationby application of a force of 500 Newtons sustained for 5 seconds.

Item 22. An automotive seat back assembly, comprising: a seat back, theseat back having the head restraint height adjustment apparatusaccording to any one of the preceding claims; a first post engagedwithin the bore of the head restraint apparatus; a second post; and ahead cushion engaged to and connecting the first and second posts.

Category 4

Item 1. A head restraint guide sleeve adapted to receive a post, whereinthe guide sleeve has a radial stiffness of no less than about 2000 N/mm,and wherein the guide sleeve is adapted such that the post interferencefit within the guide sleeve can translate axially therein upon an axialsliding force of no greater than about 30 N.

Item 2. The head restraint guide sleeve according to item 1, wherein theguide sleeve is adapted to provide a radial stiffness of no less thanabout 2,250 N/mm, no less than about 2,500 N/mm, no less than about2,750 N/mm, no less than about 3,000 N/mm, no less than about 3,500N/mm, no less than about 4,000 N/mm.

Item 3. The head restraint guide sleeve according to any one of thepreceding items, wherein the guide sleeve is adapted such that the postcan translate axially therein upon an axial sliding force of no greaterthan 29 N, no greater than 28 N, no greater than 27 N, no greater thanabout 26 N, no greater than about 25 N, no greater than about 24 N, nogreater than about 23 N, no greater than about 22 N, no greater thanabout 21 N, no greater than about 20 N, no greater than about 19 N, nogreater than about 18 N, no greater than about 17 N, no greater thanabout 16 N, no greater than about 15 N, no greater than about 14 N, nogreater than about 13 N.

Item 4. The head restraint guide sleeve according to any one of thepreceding items, wherein the guide sleeve comprises a metal substrateand a low friction layer.

Item 5. The head restraint guide sleeve according to item 4, wherein thelow friction layer comprises a polymer, such as a fluoropolymer, such asPTFE.

Item 6. The head restraint guide sleeve according to any one of items 4or 5, wherein the low friction layer is welded, adhered, or mechanicallyinterlocked with the metal substrate.

Item 7. The head restraint guide sleeve according to any one of items1-6, wherein the guide sleeve further comprises a plurality of wavestructures.

Item 8. The head restraint guide sleeve according to item 7, whereineach of the plurality of wave structures extend radially inward.

Item 9. The head restraint guide sleeve according to any one of thepreceding items, wherein the guide sleeve comprises a central axis, andwherein a portion of the guide sleeve comprises at least three wavestructures when viewed in a cross-section with respect to the centralaxis of the guide sleeve.

Item 10. The head restraint guide sleeve according to any one of items7-9, wherein the guide sleeve has an axial length, L_(GS), and whereinthe guide sleeve has at least one feature selected from the followingfeatures:

-   -   (i) each wave structure has an axial length, L_(WS), wherein        L_(WS) is no less than about 0.25 L_(GS); or    -   (ii) wherein there are at least two rows of wave structures.

Item 11. The head restraint guide sleeve according to any one of items7-10, wherein each of the plurality of wave structures has a generallyarcuate shape defining an apex.

Item 12. The head restraint guide sleeve according to item 11, whereineach apex is adapted to provide a point contact location.

Item 13. The head restraint guide sleeve according to item 11, whereineach apex has a planar portion adapted to provide an area contactlocation.

Item 14. The head restraint guide sleeve according to any one of thepreceding items, wherein the guide sleeve has an initial diameter,D_(I), wherein the guide sleeve has an operational diameter, D_(O), andwherein D_(O) is less than D_(I).

Item 15. The head restraint guide sleeve according to item 14, wherein aratio of D_(I):D_(O) is no less than 0.4, no less than 0.5, no less than0.6, no less than 0.7, no less than 0.8, no less than 0.9, no less than0.95, no less than 0.96, no less than 0.97, no less than 0.98, no lessthan 0.99.

Item 16. The head restraint guide sleeve according to any one of items14-15, wherein a ratio of D_(I):D_(O) is no greater than 0.999, nogreater than 0.995, no greater than 0.990, no greater than 0.985, nogreater than 0.980, no greater than 0.975, no greater than 0.970, nogreater than 0.950, no greater than 0.925, no greater than 0.900.

Item 17. The head restraint guide sleeve according to any one of items14-16, wherein the post has an outer diameter, D_(P), and wherein aratio of D_(P):D_(I) is no less than 1.005, no less than 1.006, no lessthan 1.007, no less than 1.008, no less than 1.009, no less than 1.010,no less than 1.011, no less than 1.012, no less than 1.013, no less than1.014, no less than 1.015, no less than 1.020, not less than 1.025, notless than 1.030.

Item 18. The head restraint guide sleeve according to item 17, whereinthe ratio of D_(P):D_(I) is no greater than 1.30, no greater than 1.25,no greater than 1.20, no greater than 1.15, no greater than 1.10.

Item 19. A head restraint preassembly, comprising:

-   -   a head restraint comprising a body and a first and second post        extending from the body;    -   a first guide sleeve engaged to the first post; and    -   a second guide sleeve engaged to the second post,    -   wherein the first guide sleeve has a radial stiffness of no less        than about 2000 N/mm, and wherein the first sleeve is slidable        along the first post upon application of a force of no greater        than about 30 N.

Item 20. The head restraint preassembly according to item 19, whereinthe first and second guide sleeves comprise a metal substrate and a lowfriction layer.

Item 21. The head restraint preassembly according to item 20, whereinthe low friction layer comprises a polymer, such as a fluoropolymer,such as PTFE.

Item 22. The head restraint preassembly according to any one of items 20or 21, wherein the low friction layer is welded, adhered, ormechanically interlocked with the metal substrate.

Item 23. The head restraint preassembly according to any one of items20-22, wherein the guide sleeves further comprise a plurality of wavestructures.

Item 24. The head restraint preassembly according to item 23, whereineach of the plurality of wave structures extend radially inward.

Item 25. The head restraint preassembly according to any one of items19-24, wherein the guide sleeves comprise a central axis, and wherein aportion of the guide sleeves comprise at least three wave structureswhen viewed in a cross-section with respect to the central axis of theguide sleeve.

Item 26. The head restraint preassembly according to any one of items19-25, wherein the guide sleeves have an axial length, L_(GS), andwherein the guide sleeves have at least one feature selected from thefollowing features:

-   -   (i) each wave structure has an axial length, L_(WS), wherein        L_(WS) is no less than about 0.25 L_(GS); or    -   (ii) wherein there are at least two rows of wave structures.

Item 27. The head restraint preassembly according to any one of items19-26, wherein each of the plurality of wave structures has a generallyarcuate shape defining an apex.

Item 28. The head restraint preassembly according to item 27, whereineach apex is adapted to provide a point contact location.

Item 29. The head restraint preassembly according to item 27, whereineach apex has a planar portion adapted to provide an area contactlocation.

Item 30. The head restraint preassembly according to any one of items19-29, wherein the guide sleeves have an initial diameter, D_(I),wherein the guide sleeves have an operational diameter, D_(O), andwherein D_(O) is less than D_(I).

Item 31. The head restraint preassembly according to item 30, wherein aratio of D_(I):D_(O) is no less than 0.4, no less than 0.5, no less than0.6, no less than 0.7, no less than 0.8, no less than 0.9, no less than0.95, no less than 0.96, no less than 0.97, no less than 0.98, no lessthan 0.99.

Item 32. The head restraint preassembly according to any one of items30-31, wherein a ratio of D_(I):D_(O) is no greater than 0.999, nogreater than 0.995, no greater than 0.990, no greater than 0.985, nogreater than 0.980, no greater than 0.975, no greater than 0.970, nogreater than 0.950, no greater than 0.925, no greater than 0.900.

Item 33. The head restraint guide sleeve according to any one of items30-32, wherein the post has an outer diameter, D_(P), and wherein aratio of D_(P):D_(I) is no less than 1.005, no less than 1.006, no lessthan 1.007, no less than 1.008, no less than 1.009, no less than 1.010,no less than 1.011, no less than 1.012, no less than 1.013, no less than1.014, no less than 1.015, no less than 1.020, not less than 1.025, notless than 1.030.

Item 34. The head restraint guide sleeve according to item 33, whereinthe ratio of D_(P):D_(I) is no greater than 1.30, no greater than 1.25,no greater than 1.20, no greater than 1.15, no greater than 1.10.

Category 5

Item 1. A head restraint guide sleeve adapted to receive a post, whereinthe guide sleeve is adapted to have an assembled radial stiffness of noless than about 1000 N/mm, and wherein the post is adapted to beinitially installed within the guide sleeve upon application of a forceof no greater than about 100 N.

Item 2. The head restraint guide sleeve according to item 1, wherein thehead restraint guide sleeve comprises: a generally cylindrical sidewall;and a plurality of wave structures extending from the generallycylindrical sidewall.

Item 3. The head restraint guide sleeve according to item 2, whereineach wave structure of the plurality of wave structures extends inwardfrom the generally cylindrical sidewall.

Item 4. A head restraint guide sleeve, comprising: a generallycylindrical sidewall; and a plurality of wave structures extendinginward from the sidewall, wherein the guide sleeve has an initialunassembled radial stiffness of less than about 1000 N/mm, and whereinthe guide sleeve is adapted to have an assembled radial stiffness, asmeasured after a post is inserted into the guide sleeve, of no less thanabout 1000 N/mm.

Item 5. A head restraint preassembly, comprising: a head restraintincluding a body and a first and second post extending from the body; afirst guide sleeve adapted to engage with the first post; and a secondguide sleeve adapted to engage with the second post; wherein the firstguide sleeve includes a generally cylindrical sidewall and a pluralityof wave structures extending inward from the generally cylindricalsidewall, wherein the guide sleeve has an initial unassembled radialstiffness of less than about 1000 N/mm, and wherein the guide sleeve isadapted to have an assembled radial stiffness, as measured after thepost is inserted into the first guide sleeve, of no less than about 1000N/mm.

Item 6. A head restraint preassembly, comprising: a head restraintincluding a body and a first and second post extending from the body; afirst guide sleeve adapted to engage with the first post; and a secondguide sleeve adapted to engage with the second post, wherein the firstguide sleeve includes a generally cylindrical sidewall and a pluralityof wave structures extending inward from the generally cylindricalsidewall, and wherein the at least one wave structure of the pluralityof wave structures includes at least one feature prior to the post beinginserted into the guide sleeve, the feature selected from the groupconsisting of: (i) an aperture extending through at least a portion ofthe at least one wave structure; or (ii) a portion having a reducedthickness; or (iii) a dimpled section.

Item 7. The head restraint guide sleeve or preassembly according to anyone of the preceding items, wherein the post is adapted to be installedwithin the guide sleeve upon application of a force of no greater thanabout 95 N, no greater than about 90 N, no greater than about 85 N, nogreater than about 80 N, no greater than about 75 N.

Item 8. The head restraint guide sleeve or preassembly according to anyone of the preceding items, wherein the guide sleeve has an assembledradial stiffness of no less than about 1100 N/mm, no less than about1200 N/mm, no less than about 1300 N/mm, no less than about 1500 N/mm,no less than about 1700 N/mm, no less than about 2000 N/mm, no less thanabout 2100 N/mm, no less than about 2200 N/mm, no less than about 2300N/mm, no less than about 2400 N/mm, no less than about 2500 N/mm, noless than about 3000 N/mm, no less than about 3500 N/mm, no less thanabout 4000 N/mm.

Item 9. The head restraint guide sleeve or preassembly according to anyone of the preceding items, wherein the guide sleeve has an initialinner diameter, D_(I), as measured along a best fit circle tangent to aninnermost surface of the guide sleeve before the post is inserted intothe guide sleeve, wherein the guide sleeve has an operational diameter,D_(O), as measured along a best fit circle tangent to an innermostsurface of the guide sleeve after the post is inserted into the guidesleeve, and wherein D_(I) is greater than D_(O).

Item 10. The head restraint guide sleeve or preassembly according toitem 9, wherein a ratio of D_(O):D_(I) is no less than about 1.0, noless than about 1.01, no less than about 1.02, no less than about 1.03,no less than about 1.04, no less than about 1.05, no less than about1.10.

Item 11. The head restraint guide sleeve or preassembly according to anyone of the preceding items, wherein the guide sleeve is adapted toabsorb an angular misalignment with the post while maintaining theassembled radial stiffness, the angular misalignment defined by amisalignment angle, A_(M), as measured by the angle between the post anda central axis of the guide sleeve, and wherein the guide sleeve isadapted to absorb an A_(M) up to about 10°, up to about 9°, up to about8°, up to about 7°, up to about 6°, up to about 5°, up to about 4°, upto about 3°, up to about 2°, up to about 1°.

Item 12. The head restraint guide sleeve or preassembly according to anyone of items 2-5 or 7-10, wherein at least one wave structure of theplurality of wave structures includes at least one feature prior to thepost being inserted into the guide sleeve, the feature selected from thegroup consisting of: (i) an aperture extending through at least aportion of the at least one wave structure; or (ii) a portion having areduced thickness; or (iii) a dimpled section.

Item 13. The head restraint guide sleeve or preassembly according to anyone of items 6-11, wherein the aperture is adapted to at least partiallyclose after the post is inserted into the first guide sleeve.

Item 14. The head restraint guide sleeve or preassembly according to anyone of items 6-12, wherein the aperture is at least partially on aninnermost surface of the at least one wave structure of the plurality ofwave structures.

Item 15. The head restraint guide sleeve or preassembly according to anyone of items 6-12, wherein the aperture is not on an innermost surfaceof the at least one wave structure of the plurality of wave structures.

Item 16. The head restraint guide sleeve or preassembly according to anyone of items 6-12 or 14, wherein the aperture extends along a sidesurface of at least one wave structure of the plurality of wavestructures.

Item 17. The head restraint guide sleeve or preassembly according to anyone of items 6-15, wherein the aperture is generally polygonal.

Item 18. The head restraint guide sleeve or preassembly according to anyone of items 6-15, wherein the aperture is generally ellipsoidal.

Item 19. The head restraint guide sleeve or preassembly according to anyone of items 6-17, wherein the aperture comprises a first tapered endand a second tapered end opposite the first tapered end, wherein thefirst and second tapered ends each comprise an acute angle, A_(A), asviewed perpendicular to the aperture, and wherein A_(A) is less thanabout 45 degrees, less than about 30 degrees, less than about 25degrees, less than about 20 degrees, less than about 15 degrees, lessthan about 10 degrees.

Item 20. The head restraint guide sleeve or preassembly according to anyone of items 6-18, wherein the aperture has a maximum length, L_(A), anda maximum width, W_(A), as measured perpendicular to L_(A).

Item 21. The head restraint guide sleeve or preassembly according toitem 20, wherein a ratio of L_(A):W_(A) is no less than about 1.0, noless than about 1.5, no less than about 2.0, no less than about 2.5, noless than about 3.0, no less than about 4.0, no less than about 5.0, noless than about 6.0, no less than about 7.0, no less than about 8.0, noless than about 9.0, no less than about 10.0, no less than about 15.0,no less than about 20.0, no less than about 25.0, no less than about30.0.

Item 22. The head restraint guide sleeve or preassembly according to anyone of items 20 or 21, wherein the ratio of L_(A):W_(A) is no greaterthan about 500, no greater than about 400, no greater than about 300, nogreater than about 200, no greater than about 100, no greater than about75, no greater than about 50, no greater than about 40.

Item 23. The head restraint guide sleeve or preassembly according to anyone of items 20-22, wherein each wave structure of the plurality of wavestructures comprises a maximum length, L_(W), and wherein a ratio ofL_(W):L_(A) is no greater than about 1.25, no greater than about 1.0, nogreater than about 0.95, no greater than about 0.90, no greater thanabout 0.85, no greater than about 0.80, no greater than about 0.75, nogreater than about 0.70, no greater than about 0.65, no greater thanabout 0.60.

Item 24. The head restraint guide sleeve or preassembly according toitem 23, wherein the ratio of L_(W):L_(A) is no less than about 0.01, noless than about 0.10, no less than about 0.20, no less than about 0.30,no less than about 0.40.

Item 25. The head restraint guide sleeve or preassembly according to anyone of items 20-24, wherein each wave structure of the plurality of wavestructures comprises a maximum width, W_(W), and wherein a ratio ofW_(W):W_(A) is no greater than about 1.25, no greater than about 1.0, nogreater than about 0.95, no greater than about 0.90, no greater thanabout 0.85, no greater than about 0.80, no greater than about 0.75, nogreater than about 0.70, no greater than about 0.65, no greater thanabout 0.60.

Item 26. The head restraint guide sleeve or preassembly according toitem 25, wherein the ratio of W_(W):W_(A) is no less than about 0.01, noless than about 0.10, no less than about 0.20, no less than about 0.30,no less than about 0.40.

Item 27. The head restraint guide sleeve or preassembly according to anyone of items 6-26, wherein each wave structure of the plurality of wavestructures has a total surface area, A_(W), wherein the portion having areduced thickness has a surface area, A_(P), and wherein a ratio ofA_(P):A_(W) is no less than about 0.05, no less than about 0.10, no lessthan about 0.15, no less than about 0.20, no less than about 0.25, noless than about 0.30, no less than about 0.35, no less than about 0.40,no less than about 0.45, no less than about 0.50, no less than about0.60, no less than about 0.70, no less than about 0.80, no less thanabout 0.90

Item 28. The head restraint guide sleeve or preassembly according to anyone of items 6-27, wherein the generally cylindrical sidewall has athickness, T_(SW), wherein the portion having a reduced thickness has athickness, T_(P), and wherein a ratio of T_(P):T_(SW) is no greater thanabout 0.99, no greater than about 0.95, no greater than about 0.90, nogreater than about 0.85, no greater than about 0.80, no greater thanabout 0.75, no greater than about 0.70, no greater than about 0.65, nogreater than about 0.60, no greater than about 0.55, no greater thanabout 0.50, no greater than about 0.40, no greater than about 0.30, nogreater than about 0.20.

Item 29. The head restraint guide sleeve or preassembly according toitem 28, wherein the ratio of T_(P):T_(SW) is no less than about 0.05,no less than about 0.10, no less than about 0.15, no less than about0.20.

Item 30. The head restraint guide sleeve or preassembly according to anyone of items 6-29, wherein the portion having a reduced thickness isadapted to have a greater radial stiffness after the post is insertedinto the guide sleeve.

Item 31. The head restraint guide sleeve or preassembly according to anyone of items 6-30, wherein the portion having a reduced thickness has aninitially unassembled radial stiffness, S₁, wherein the portion having areduced thickness has an assembled stiffness after the post is insertedinto the guide sleeve, S₂, and wherein a ratio of S₂:S₁ is no less thanabout 1.01, no less than about 1.05, no less than about 1.10, no lessthan about 1.20, no less than about 1.30, no less than about 1.40, noless than about 1.50, no less than about 1.75, no less than about 2.00.

Item 32. The head restraint guide sleeve or preassembly according to anyone of items 6-31, wherein the dimpled section is adapted to have agreater radial stiffness after the post is inserted into the guidesleeve.

Item 33. The head restraint guide sleeve or preassembly according to anyone of items 6-32, wherein the dimpled section comprises a corrugation.

Item 34. The head restraint guide sleeve or preassembly according to anyone of items 6-33, wherein the dimpled section comprises a plurality ofcorrugations.

Item 35. The head restraint guide sleeve or preassembly according to anyone of items 6-34, wherein the dimpled section comprises a perforation.

Item 36. The head restraint guide sleeve or preassembly according to anyone of items 6-35, wherein the dimpled section comprises a plurality ofperforations.

Item 37. The head restraint guide sleeve or preassembly according to anyone of items 6-36, wherein the dimpled section extends inward from aninnermost surface of the at least one wave structure.

EXAMPLES

The radial stiffness of a head restraint assembly is tested by firstinserting a post into a bearing. The post is held stationary at a firstlongitudinal position while a perpendicular normal force is appliedagainst an outer surface of the bearing at a second longitudinalposition. The normal force is gradually increased (e.g., 100 N, 200 N,300 N, 400 N, etc.) to 1000 N and the resulting radial displacement ofthe bearing relative to the post is measured.

Sample 1 comprises a bearing and post in accordance with the presentinvention. In particular, the bearing is formed from a multilayercomposite (i.e. 3 layers) comprising an outer flouropolymer slidinglayer comprising PTFE, a steel substrate and a thin inner sliding layerto prevent metal to metal contact between the bearing and the post. Thebearing further comprises four wave structures extending radiallyinward. The projections have a radial length of 1.0 mm, as measured fromthe inner surface of the bearing, and engage the posts at four contactlocations. The initial diameter of the bearing, as measured by a bestfit circle tangent to the inner contact surface of the wave structuresis approximately 13.78 mm. The post is formed from steel and has adiameter of 14 mm. The normal force is applied against the bearing at arate of 0.3 mm/min.

Sample 2 comprises a bearing formed from plastic having a cylindricalbody with cutout tines extending radially inward. The tines comprise aplastic material contiguous with the cylindrical body. The initial innerdiameter of the bearing is approximately 20.60 mm with each of the tinesinitially projecting radially inward a maximum radial distance ofapproximately 0.93 mm. A post is inserted into the bearing. The post isformed from steel and has a diameter of 19.60 mm. The normal force isapplied against the bearing at a rate of 0.3 mm/min. The results areshown in Table 1.

TABLE 1 Radial Stiffness Sample Radial Stiffness 1 4421 N/mm 2  943 N/mm

As illustrated in Table 1, Sample 1 has a radial stiffness of 4421 N/mm,whereas Sample 2 has a radial stiffness of 943 N/mm. Thus, the assemblyof Sample 1 can provide at least a 468% increase in radial stiffness ascompared to the assembly of Sample 2.

The axial sliding force (i.e., the force necessary to axially translatethe posts within the bearing) is tested by first inserting a post atleast partially into a bearing (i.e. such that the post engages with theprojections of the bearing). The bearing is held stationary while aforce directed axially along the length of the post is applied againstthe axial end of the post. The force is increased until the post beginsto translate longitudinally within the bearing, and the resulting forcerequired throughout the translation is measured. The results are shownin Table 2. It is noted that the maximum axial force was found duringthe initial stages of movement when the assemblies were required toovercome the effects associated with static friction.

TABLE 2 Sliding Forces Sample Average Axial Force (N) Maximum AxialForce (N) 1 12.8 27.50 2 39.62 53.63

As illustrated in Table 2, Sample 1 requires a maximum axial force toexhibit movement of 27.50 N, whereas Sample 2 requires a maximum axialforce of 53.63 N. Thus, Sample 1 can translate within the bearing upon amaximum axial force that is less than 52% the maximum axial forcerequired to translate the post of Sample 2

As illustrated in Table 2, Sample 1 required an average axial forcethroughout sliding of 12.8 N, whereas Sample 2 required an average axialforce throughout sliding of 39.62 N. Thus, Sample 1 can freely translatewithin the bearing upon an average axial force that is less than 33% theaverage axial force required to translate the post of Sample 2. Manydifferent aspects and embodiments are possible. Some of those aspectsand embodiments are described below. After reading this specification,skilled artisans will appreciate that those aspects and embodiments areonly illustrative and do not limit the scope of the present invention.Embodiments may be in accordance with any one or more of the items aslisted below.

Note that not all of the activities described above in the generaldescription or the examples are required, that a portion of a specificactivity may not be required, and that one or more further activitiesmay be performed in addition to those described. Still further, theorder in which activities are listed is not necessarily the order inwhich they are performed.

Benefits, other advantages, and solutions to problems have beendescribed above with regard to specific embodiments. However, thebenefits, advantages, solutions to problems, and any feature(s) that maycause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeature of any or all the claims.

The specification and illustrations of the embodiments described hereinare intended to provide a general understanding of the structure of thevarious embodiments. The specification and illustrations are notintended to serve as an exhaustive and comprehensive description of allof the elements and features of apparatus and systems that use thestructures or methods described herein. Separate embodiments may also beprovided in combination in a single embodiment, and conversely, variousfeatures that are, for brevity, described in the context of a singleembodiment, may also be provided separately or in any subcombination.Further, reference to values stated in ranges includes each and everyvalue within that range. Many other embodiments may be apparent toskilled artisans only after reading this specification. Otherembodiments may be used and derived from the disclosure, such that astructural substitution, logical substitution, or another change may bemade without departing from the scope of the disclosure. Accordingly,the disclosure is to be regarded as illustrative rather thanrestrictive.

What is claimed is:
 1. A head restraint preassembly comprising: a headrestraint including a body and a first and second post extending fromthe body; a first guide sleeve adapted to engage with the first post;and a second guide sleeve adapted to engage with the second post;wherein the first guide sleeve includes a generally cylindrical sidewalland a plurality of wave structures extending radially from the generallycylindrical sidewall, wherein the first guide sleeve has an initialunassembled radial stiffness, wherein the first guide sleeve is adaptedto have an assembled radial stiffness, as measured after the first postis inserted into the first guide sleeve, and wherein the initialunassembled radial stiffness is less than the assembled radialstiffness.
 2. The head restraint preassembly according to claim 1,wherein at least one wave structure of the plurality of wave structuresincludes at least one feature prior to the first post being insertedinto the first guide sleeve, the feature including: an apertureextending through a portion of the at least one wave structure; aportion having a reduced thickness; a dimpled section; a partiallydisconnected wave structure; or any combination thereof.
 3. The headrestraint preassembly according to claim 2, wherein the partiallydisconnected wave structure comprises a wave structure disconnected fromthe adjacent undeformed portion of the sidewall along at least two sidesof the wave structure.
 4. The head restraint preassembly according toclaim 2, wherein the generally cylindrical sidewall has a thickness,T_(SW), wherein the portion having a reduced thickness has a thickness,T_(P), and wherein a ratio of T_(P):T_(SW) is no greater than about0.99.
 5. The head restraint preassembly according to claim 2, whereinthe portion having a reduced thickness is adapted to have a greaterradial stiffness after the post is inserted into the guide sleeve. 6.The head restraint preassembly according to claim 2, wherein the portionhaving a reduced thickness has an initially unassembled radialstiffness, S₁, wherein the portion having a reduced thickness has anassembled stiffness after the post is inserted into the guide sleeve,S₂, and wherein a ratio of S₂:S₁ is no less than about 1.01.
 7. The headrestraint preassembly according to claim 1, wherein the first guidesleeve is adapted to translate relative to the first post uponapplication of a force of no greater than 30 N.
 8. The head restraintpreassembly according to claim 1, wherein the undeformed portion of thesidewall and the plurality of wave structures are of unitaryconstruction.
 9. The head restraint preassembly according to claim 1,wherein the first guide sleeve comprises a composite structure includinga metal substrate and a low friction polymer layer.
 10. The headrestraint preassembly according to claim 9, wherein the low frictionpolymer layer comprises a PTFE.
 11. The head restraint preassemblyaccording to claim 1, wherein the first guide sleeve has a radialstiffness of no less than 2,000 N/mm, and wherein the first sleeve isadapted to translate along the first post upon application of a force ofno greater than 30 N.
 12. The head restraint preassembly according toclaim 1, wherein each of the plurality of wave structures protruderadially inward toward a central axis of the first guide sleeve.
 13. Thehead restraint preassembly according to claim 1, wherein the first guidesleeve has an axial length, L_(GS), and wherein: each wave structure ofthe first guide sleeve has an axial length, L_(WS), that is no less than0.25 L_(GS); the plurality of wave structures define at least twocircumferentially extending rows around the first guide sleeve; or acombination thereof.
 14. The head restraint preassembly according toclaim 1, wherein the head restrain assembly further comprises a lockingmechanism adapted to selectively secure the first post relative to thefirst guide sleeve, wherein the locking mechanism is detachably coupledto the generally cylindrical sidewall.
 15. The head restraintpreassembly according to claim 14, wherein the locking mechanismcomprises a different material than the generally cylindrical sidewalland wherein the locking mechanism is rotatably coupled to the firstguide sleeve.
 16. The head restraint preassembly according to claim 14,wherein the first post has an adjustment length, and wherein the lockingmechanism is adapted to secure the first guide sleeve at any locationalong the adjustment length.
 17. The head restraint preassemblyaccording to claim 1, wherein the first guide sleeve has an initialunassembled radial stiffness of less than about 1000 N/mm, and whereinthe guide sleeve is adapted to have an assembled radial stiffness, asmeasured after the post is inserted into the first guide sleeve, of noless than about 1000 N/mm.
 18. The head restraint preassembly accordingto claim 1, wherein the first guide sleeve has an initial innerdiameter, D_(I), as measured along a best fit circle tangent to aninnermost surface of the guide sleeve before the post is inserted intothe guide sleeve, wherein the guide sleeve has an operational diameter,D_(O), as measured along a best fit circle tangent to an innermostsurface of the guide sleeve after the post is inserted into the guidesleeve, and wherein D_(I) is greater than D_(O).
 19. The head restraintpreassembly according to claim 18, wherein a ratio of D_(O):D_(I) is noless than about 1.0.
 20. The head restraint preassembly according toclaim 1, wherein the first guide sleeve is adapted to absorb an angularmisalignment with the post while maintaining the assembled radialstiffness, the angular misalignment defined by a misalignment angle,A_(M), as measured by the angle between the post and a central axis ofthe guide sleeve, and wherein the guide sleeve is adapted to absorb anA_(M) up to about 10.